Research team

Condensed Matter Theory

Expertise

- Modelling of semiconductors and of electrical and magnetic processes.

Flat bands and electron correlations in graphene. 01/01/2021 - 31/12/2024

Abstract

From the moment it was isolated as a 2D material, graphene has become a remarkable subject of research, exhibiting novel phenomena that extend to almost any domain within condensed matter physics and physical chemistry. Recently, this was further extended with the discovery of 'magic-angle graphene', in which twisted bilayer graphene (TBG) with nearly flat bands was observed to behave as a high-temperature superconductor - the Physics World 2018 Breakthrough of the Year. However, TBG remains extremely challenging to fabricate which, together with intrinsic constraints on tunability, limit further research on the electron correlation phenomena emerging from its flat bands. Here we propose to explore an alternative system, based on periodic lattices of strained nanobubbles in single-layer graphene, which host similar flat bands to those in TBG, with the advantage of being much more tunable (e.g. allowing for even flatter bands) and scalable (crucial for further fundamental studies as well as eventual applications). The fabrication is based on an original approach that combines ultra-low energy ion implantation (a unique technique developed by the consortium) and state-of-the-art nanofabrication. The tunability of the fabrication approach, together with the unique expertise of the consortium on theoretical tools for electronic structure calculations of such systems, will allow us to produce specific electron correlation phenomena (superconductivity and magnetism) by design.

Researcher(s)

Research team(s)

Piezo and flexoelectricity driven by inhomogeneous strain in 2D materials. 01/10/2020 - 30/09/2023

Abstract

Electromechanical properties play an essential role in determining the physics of dielectric solids and their practical application. Popularly, electrostriction, and the piezoelectric effect were considered to be the two main electromechanical effects that couple an applied electric field to the strain and vice versa. The coupling between polarization and strain gradients is another electromechanical phenomenon, which can be observed by bending a material. This is known as flexoelectricity, which is present in a much wider variety of materials, including non-polar dielectrics and polymers, but is only significant at small length-scales, where high strain-gradients develop. In two dimensional (2D) materials, where large strain gradients are possible, these effects are expected to be strongly enhanced. Besides, the superior elastic properties and reduced lattice symmetry makes 2D materials promising for flexoelectricity. In this proposal, by using state of the art ab initio approaches, fundamental flexoelectric properties of a wide variety of 2D materials will be investigated. Subsequently, a multiscale modeling framework that captures the influence of internal-strain gradients on the electronic and optical properties will be developed. The work proposed here will not only provide a fundamental understanding of flexoelectricity in 2D materials but will also guide the discovery of new flexible electronics.

Researcher(s)

Research team(s)

Tailoring plasmonics in van der Waals heterostructures. 01/10/2019 - 30/09/2022

Abstract

This research proposal aims at untangling and modelling the plasmonic properties of various van der Waals heterostructures and at using these models to construct new tailor-made structures that host unique types of plasmons. By changing the composition and structural properties of heterostructures, we will be able to uncover novel ways to manipulate light at sub-wavelength length scales by coupling it to collective excitations of the electron liquid, so-called plasmons. Van der Waals heterostructures are stacks of different types of atomically thin two-dimensional materials. In the wake of the discovery of graphene, a single layer of graphite, many other atomically thin crystals have been discovered and each of them has its own electronic behavior ranging from insulators over semiconductors and semimetals to even superconductors. We are now in a unique position to combine different two-dimensional crystals in a single stack and to construct tailor-made heterostructures in which the properties of the individual materials can be used in concert. In this project I will investigate various heterostructures in order to extend our understanding of the behavior of plasmons in these materials, and furthermore to uncover plasmons with unprecedented characteristics. The proposed work will be done in close collaboration with foreign experimental groups that will provide necessary feedback to improve the models and to test the plasmonic response of proposed heterostructures.

Researcher(s)

Research team(s)

Computational modeling of materials: from atomistic properties to new functionalities. 01/01/2019 - 31/12/2023

Abstract

The WOG "Computational modeling of materials" aims to: - Promote interdisciplinary computational material research, bringing together groups from physics, chemistry and materials science, and providing them with a platform on which to share their expertise in order to arrive at an integrated and pragmatic approach in order to develop opto-electronic, thermodynamic and structural properties of materials to study. - Develop new techniques and implement them in computer software that can be subsequently used in either academic or industrial contexts

Researcher(s)

Research team(s)

Atomic thin membranes for water and ion transport. 01/01/2019 - 31/12/2022

Abstract

Membranes are used for different separation processes with applications in areas as diverse as water desalination, gas separation, energy technologies, microfluidics and medicine. Due to its atomic thickness and its exceptional mechanical properties, graphene and related materials have opened up new possibilities in membrane technologies. Such membranes will be investigated for water and hydrogen transport, ion sieving and hydrogen isotope separation. Fundamental insights into mass transport at the nanoscale will be obtained through theoretical and computational modelling with intensive collaboration with experimentalists for validation.

Researcher(s)

Research team(s)

Tunable in-plane and out-of-plane anisotropy in two dimensional materials. 01/10/2018 - 30/09/2021

Abstract

Two-dimensional (2D) single-layer materials are currently a very important topic in materials science because of their unique properties. A particular class of such materials are one those with low symmetry and with anisotropy which are important candidates for various applications in nanotechnology ranging from optoelectronic to spin-based devices and even to field effect transistors (FET) and nano optical waveguide polarizers. The prediction of novel stable anisotropic single-layer crystals and a deeper understanding of their physical properties is very important. The understanding of their Raman spectrum is essential in distinguishing between the different structural phases and in determining the crystal orientation of the material. The present project puts forward a method to determine the crystal orientation of anisotropic materials through resonant Raman measurements from both first- and second-order Raman spectra. I will contribute to the study of first- and second-order resonant Raman scattering in anisotropic materials, from which information on the electron-phonon and exciton-phonon interactions can be obtained. These are very important for the understanding of light-matter interactions. Moreover, 2D materials are often subject to external forces such as strain and charge transfer to or from the substrate. Therefore, these effects on the physical properties of anisotropic materials will be thoroughly investigated.

Researcher(s)

Research team(s)

Understanding and tuning of light matter interactions in transition metal dichalcogenides monolayers and their heterostructures (QuantumTMDs). 01/05/2019 - 30/04/2020

Abstract

Fundamental understanding and control of quantum phenomena on unprecedented length and time scales are essential for proper development of next generation devices. Recent advances in the synthesis of atomically thin layers of van der Waals solids such as graphene, boron nitride, and transition metal dichalcogenides (TMD) open up possibilities to success, for example, in computing, information and energy technology. Related to photonics and optoelectronics applications monolayer TMDs have potential for increasing the capabilities of conventional semiconductors by broad absorption spectrum, i.e., from near-infrared to the visible region. In this proposal, we will study the light matter interactions in monolayer TMDs and their heterostructures with emphasis on strong excitonic effects, and spin- and valley-dependent properties. To this end, we will develop model Hamiltonian techniques, which in conjunction with density functional theory based calculations will provide new insight in the light matter interactions in monolayer TMDs. The overarching goal of this proposal is to achieve understanding of novel quantum phenomena in monolayer TMDs in particular how heterostructuring, defects, and strain intertwine to produce interesting physical properties. The work proposed here will lead to major advances in understating how defects, heterostructuring, and strain modify the properties of 2D materials, resulting in novel quantum phenomena.

Researcher(s)

Research team(s)

Tight-binding model and effective Hamiltonian for twodimensional materials. 01/03/2019 - 31/08/2019

Abstract

A wide range of two-dimensional (2D) materials ranging from graphene to topological insulators share the extraordinary phenomenon that electrons behave as relativistic particles in their low-energy excitations in different formats such as Dirac cones, Dirac nodal lines and Weyl nodes and so on. These emergent behaviors of fermions in condensed matter systems have attracted both experimental and theoretical researches. Density functional theory is a good point to start calculating the electronic properties of materials, but this method is unable to find all properties of the system. One of the most important methods to calculate the electronic properties of such systems is the Green's function approach. In this method the tight-binding (TB) model explains the physical system. Therefore we need to define a TB model and find the hopping coefficients between atoms and orbitals. With the linear combination of atomic orbitals (LCAO) method the system can be described by a set of non-interacting single-particles. By using the simplified LCAO method in combination with firstprinciples calculations, we are able to construct TB models in the two-centre approximation for 2D materials. The Slater and Koster (SK) approach is a powerful method to reproduce the first-principles data and construct the TB model. This method is applied to calculate the TB Hamiltonian of these systems based on the s, p and d orbitals. We obtain expressions for the Hamiltonian and overlap matrix elements between different orbitals for the different atoms and present the SK coefficients in a nonorthogonal basis set.

Researcher(s)

Research team(s)

Atomic collapse in Dirac-like materials. 01/10/2018 - 02/06/2020

Abstract

Soon after the formulation of the Dirac equation (1928), which describes relativistic particles, it was predicted that for a high charge Z of the nucleus the atom becomes unstable, leading to the phenomenon of atomic collapse. Because of the large required Z>170 value scientists were never able to verify it experimentally. However, the discovery of graphene and the fact that its charge carriers mimic relativistic (quasi-)particles opened up a new window on atomic collapse, which was recently observed experimentally in graphene. Using this recent observation as motivation, we will theoretically investigate the atomic collapse phenomenon in graphene and other Dirac-like materials having very different energy dispersions. We will study how the various differences between these materials influence the atomic collapse phenomenon and study how this phenomenon can be tuned by external electric and magnetic fields. The purpose of this proposal is two fold: 1) to study atomic collapse in different Dirac-like materials, which will give us fundamental information and understanding about atomic collapse at the relativistic level, and 2) to investigate the influence of atomic collapse on the transport of charge carriers in Dirac-like materials, providing us with very important information needed for the development of future applications .

Researcher(s)

Research team(s)

Novel Magnetic Two-dimensional Materials. 01/10/2018 - 30/09/2019

Abstract

The scope of the proposed project is to investigate the magnetic properties of recently emerged two-dimensional (2D) materials having intrinsic magnetism. Nanoscale magnetism is of great scientific interest and has high technological relevance. Since the discovery of graphene, twodimensional materials have drawn considerable attention due to their extraordinary physical properties and potential application in nanoscale magneto-electronics, so-called spintronics. Although most of the 2D materials do not exhibit magnetism, the search for intrinsic ferromagnetism in the monolayer limit did not end. Motivated by the recent discovery of the ferromagnetic monolayer CrI3 and its number of layers dependent magnetic phase transitions we propose to use density functional theory to predict other 2D ferromagnetic materials. Furthermore, we want to understand the formation mechanisms and stability of magnetism in 2D materials and possible routes of tuning it by external stimuli such as strain, charge doping, and electric field.

Researcher(s)

Research team(s)

Moiré patterns induced in bilayer van der Waals heterostructures 01/10/2017 - 30/09/2020

Abstract

Two-dimensional (2D) materials are currently a very important topic in materials science due to their unique properties and high crystal quality. An important property of these materials is that they can be stacked on top of each other regardless of the mismatch between the unit cells and with almost any twist angle between the two lattices. This is thanks to the weak van der Waals interaction that acts between different layers. However, researchers have found that the properties of these stacked structures can be very different from its constituents, they not only dependent on the choice of 2D materials used for its construction but are also significantly influenced by the orientation of the two lattices. A difference in lattice constant and/or misorientation of the two lattices results in the appearance of a periodic superlattice structure called moiré pattern. Thus, the types of 2D materials used for stacking and the period of moiré pattern can be in principle used for the design of novel materials with desirable properties. In this project we will focus on the formation of moiré patterns as generated by stacking two monolayers on top of each other and their consequences on the different physical properties of the heterostructure. The effect of internal and external applied strain will be considered.

Researcher(s)

Research team(s)

Few-body correlation effects in transition metal dichalcogenide monolayers. 01/10/2017 - 30/09/2019

Abstract

Since the celebrated discovery of graphene, there has been a growing interest in two dimensional (2D) crystals for potential applications in next-generation nanoelectronic devices. Transition-metal dichalcogenides (TMDs) are a very promising class of materials that can be shaped into monolayers. Recently there has been increasing interest in these systems both theoretically and experimentally because of their particular properties. The strong Coulomb interaction in TMD monolayers makes these systems an excellent candidate for the study of different stronglycorrelated phases in 2D atomic crystals. The focus of this proposal is on excitonic effects in TMD mono- and multi-layers. I plan to investigate excitons, trions (charged excitons) and biexcitons. Recently, the stability and binding energy of these quasi-particles have been measured. The aim of my proposal is to numerically obtain the electronic and optical properties of excitons, trions and biexcitions in TMD layers and compare them with experimental data. The second part of the proposal deals with the study of excitonic superfluid properties in a system of double-TMD monolayers. I plan to show that coupled parallel TMD monolayers can be a very promising system for observing high-temperature superfluidity. This conviction is based on recent advances in fabricating TMD van der Waals heterostructures and the analogy of the system with double-bilayer graphene in which high-temperature superfluidity was predicted.

Researcher(s)

Research team(s)

Design of opto-electronic properties in two dimensional materials by enhanced flexoelectric coupling. 01/01/2017 - 31/12/2020

Abstract

Electromechanical effects, such as piezo- and flexoelectricity, are a consequence of the coupling of an applied electric field to the strain and the strain gradient, respectively. These effects are expected to be strongly enhanced in two dimensional materials (2D), first, due to the reduction in lattice symmetries in the 2D limit, and second, due to the superior elastic properties, allowing strains even up to 10% in some cases. Furthermore, 2D materials are fully flexible and bendable, thus ushering a new era of flexible opto-electronic devices. In this proposal, we will first investigate the fundamental flexoelectric properties of a wide variety of 2D materials by using a combination of analytical and ab-initio approaches. Important questions related to the magnitude of the coupling coefficients, the effect of phonon anharmonicity and the identification of materials with optimal electro- and mechanical properties will be answered. Subsequently we will model specific strain configurations as out-of-plane (ripples, folds, kirigami) and in-plane geometries (patterned layers, heterostructures, etc.). These are of significant importance because, as opposed to bulk electromechanical effects, modifications at the nanoscale in 2D materials greatly affect their optoelectronic properties. As concrete examples we will investigate the possibility of creating flexotransistors or flexo-photovoltaic devices.

Researcher(s)

Research team(s)

Investigation of prototype devices in two-dimensional materials. 01/10/2016 - 30/09/2019

Abstract

The exploration of novel low dimensional atomically thin materials is very important for a future generation of flexible nanoelectronics, optoelectronics, and energy storage devices. Among these, graphene has demonstrated a wide range of properties including, high electrical and thermal conductivity, and optical transparency. Due to the semiconducting nature of transition metal dichalcogenides, they are also becoming promising candidates. More recently, high frequency devices containing few layer black phosphorous have been demonstrated. Combining these materials in heterostructures would lead to a many-fold enhancement in their functionalities. In this proposal, with the combined effort of the two teams, prototype devices containing 2D heterostructures will be investigated. A deep understanding of the stability and electronic properties of heterostructures, investigated by the Chinese team with the use of ab-inito simulations will be coupled to effective models of prototype devices, either at tight binding or continuum level, led by the Belgian team. Systems comprised of vertical and in-plane heterostructures will be used to propose candidate devices taking advantage of either the charge or spin degrees of freedom. Of special interest are also tunable opto-electronic and excitonic effects. It is expected that this collaborative effort will lead to both a fundamental understanding of optoelectronic processes and the modeling of specific nano- and microelectronic devices.

Researcher(s)

Research team(s)

Exploring the frontiers of optics of Dirac materials. 01/10/2016 - 30/09/2019

Abstract

This proposal aims at exploring the frontiers of the optics of Dirac materials. By modelling how light interacts with two and three dimensional Dirac materials, we want to access the peculiar world of electrons with very unconventional properties. We will image how the sea of electrons reacts to an external light source. On the one hand, we want to use this light source to measure how viscous the sea of electrons is. For example, whether it is more like honey, a viscous fluid, or more like water, a less viscous fluid. On the other hand, we will put forward proposals to extend the lifetime of plasmons in Dirac materials. Plasmons can be thought of as a wave in the sea of electrons. In this wave the electrons and the incident light are coupled with each other and move around coherently. It is possible to manipulate these plasmons in order to guide light in the direction you want and use them for photonic applications. However, it remains a challenge to find systems in which the plasmons live long enough to be useful. Therefore, we will investigate whether it is possible to take advantage of particular properties of the crystal or external electric currents to make the plasmons more robust and extend their lifetime. The proposed work will be done in close collaboration with several foreign experimental groups that will provide the necessary feedback to improve our models and to verify the proposed physics.

Researcher(s)

Research team(s)

Research in the field of condensed matter theory. 01/10/2016 - 30/09/2017

Abstract

Objectives of the sabbatical year: - Defining new innovative lines of research for my research group - Recharging - Develop new collaborations with mainly experimental groups - Strengthen existing partnerships

Researcher(s)

Research team(s)

Nanostructured graphene. 01/09/2016 - 28/02/2017

Abstract

Study of energy levels in graphene nanostructures. The confined states in three different graphene systems were considered: 1) monolayer-bilayer graphene quantum dots (QDs), 2) trilayer graphene QDs, and 3) hybrid monolayer-bilayer interfaces. As a new project, we investigate the existence of confined massless fermion states in a graphene quantum well by means of analytical and numerical calculations. Our proposal is based on the fact that the transmission coefficient through both barriers and wells in graphene displays a strong angular dependence. The trigonal warping effect can suppress this tunneling and thus allow the confinement of electrons. We also propose to calculate electrical conductivity along the quantum well direction. We will investigate if there is any dependence of the electrical conductivity on the specific direction of the quantum well with respect to the graphene lattice. The idea is that this would lead to the realization of a novel type of graphene wire where conduction is not influenced by the boundaries. The aim of our project is to guide experimental research towards confinement of carriers in graphene nanostructures.

Researcher(s)

Research team(s)

Functional properties of two-dimensional nanostructured materials. 01/01/2016 - 31/12/2020

Abstract

With the proposed scientific research community involved research teams want to create the necessary critical mass to successfully combine self-organization and more generally surface modification for inducing improved as well as new functionalities with the ultimate aim to tune the electronic, magnetic and spintronic, mechanical, and optical properties. We want to achieve the following goals: • Understanding the influence of controlled surface modification on the functionalities and the applicability of 2D materials, including topological insulator surfaces. • Understanding the influence of contamination that can be present on the surface as well as at the interface with the substrate. • Exploring the modified and novel properties resulting from the low dimensionality, including quantum-mechanical effects. • A major strength of the proposed consortium is that there will be a very close interaction between the experimentally oriented research groups and the groups that focus on the theoretical modeling of the modified 2D materials.

Researcher(s)

Research team(s)

Theoretical investigation of electronic transport in functionalized 2D transition metal dichalcogenides (Trans2DTMD). 01/01/2016 - 31/12/2018

Abstract

Metallic transition metal dichalcogenide (TMD) monolayers are promising ultrathin materials which have the potential to complete the range of graphene-related materials by offering tunable metallic phases with strong spin-orbit coupling. Many of them can be achieved by small structural deformations and doping of Group 6 TMDs and thus could thus be used as electrode materials within a single monolayer, resulting in a very low contact resistance. Experimental study of metallic TMDs is difficult as these phases are often metastable or rely on very subtle structural modifications. Thus, a careful theoretical investigation is imperative before complex experimental studies should be pursued. This consortium will investigate metallic TMD structures, including intrinsically metallic phases, metastable metallic phases, and external factors to trigger semiconductor-metal transitions such as doping, defects and strain. Special attention will be given to spin-orbit splitting and ways to control them. Computer simulations will range from band-structure calculations of small unit cells to rather complex systems, including heterostructures, doped and defected systems up to grain boundaries. Conclusions on the suitability of these materials in practical application will be further confirmed by explicit transport calculations and device simulations. While most calculations can be carried out using state-of-the-art software, some method developments are necessary and will be carried out here. Numerical methods that scale linearly with the system size, O(N), will be developed by using a polynomial expansion of the components of the conductivity tensor. These will allow for simulations of large unit cells in the presence of disorder and the calculation of spin- and valley- dependent contributions. It will become therefore suitable to describe the Spin and Valley Hall effects in realistic models of TMDs.

Researcher(s)

Research team(s)

Two-dimensional atomic crystals as building blocks of new heterostructures. 01/10/2015 - 30/09/2018

Abstract

Nanotechnology is an emerging multidisciplinary field that is revolutionizing materials science and optoelectronics. Since the future of this new technology will be shaped by the accessible materials, searching for new materials with novel functionalities will be crucial. The present proposal aims to make significant contributions to the engineering of heterostructures composed of atomically-thin crystal structures. Currently, the research on atomic-scale heterostructures is in its earliest stage and the number of available materials is rather limited. The stability and electronic properties of novel atomically-thin crystal structures will be investigated using state-of-the-art computational techniques. Density Functional Theory, will be used by the applicant, which is a quite powerful tool used in condensed matter physics, chemistry and biophysics to investigate the electronic and magnetic properties of many-body systems. In the second part, monolayer crystal structures that have desired properties will be used as building blocks of nanoscale heterostructures. The possibility of using such heterostructures in various optoelectronic devices such as Schottky diodes, PN junctions and spin-valves will be examined.

Researcher(s)

Research team(s)

Few-body correlation effects in transition metal dichalcogenide monolayers. 01/10/2015 - 30/09/2017

Abstract

Since the celebrated discovery of graphene, there has been a growing interest in two dimensional (2D) crystals for potential applications in next-generation nanoelectronic devices. Transition-metal dichalcogenides (TMDs) are a very promising class of materials that can be shaped into monolayers. Recently there has been increasing interest in these systems both theoretically and experimentally because of their particular properties. The strong Coulomb interaction in TMD monolayers makes these systems an excellent candidate for the study of different stronglycorrelated phases in 2D atomic crystals. The focus of this proposal is on excitonic effects in TMD mono- and multi-layers. I plan to investigate excitons, trions (charged excitons) and biexcitons. Recently, the stability and binding energy of these quasi-particles have been measured. The aim of my proposal is to numerically obtain the electronic and optical properties of excitons, trions and biexcitions in TMD layers and compare them with experimental data. The second part of the proposal deals with the study of excitonic superfluid properties in a system of double-TMD monolayers. I plan to show that coupled parallel TMD monolayers can be a very promising system for observing high-temperature superfluidity. This conviction is based on recent advances in fabricating TMD van der Waals heterostructures and the analogy of the system with double-bilayer graphene in which high-temperature superfluidity was predicted.

Researcher(s)

Research team(s)

Many-body physics of coupled graphene multilayers. 01/01/2015 - 31/12/2018

Abstract

The key questions we plan to answer are: - How many graphene layers are needed in order to make quantum Wigner crystallization possible? - Which crystal phases are possible and what is the phase diagram (and its dependence on the different tuning parameters)? - What is the effect of the dielectric environment on excitonic superfluidity in spatially separated electron hole layers of few layer graphene? - How does the critical temperature depend on the number of graphene layers in each sheet and on the carrier density (and on the other tuning parameters)?

Researcher(s)

Research team(s)

Many-body effects in single- and multi-layers of graphene. 01/10/2014 - 30/09/2016

Abstract

This proposal aims to explore novel effects induced by electron-electron interaction, with or without magnetic fields, in graphene and multi-layer graphene. Investigation of plasmons in such systems and in related 2D atomic crystals.

Researcher(s)

Research team(s)

Modulating the electronic structure of two-dimensional heterostructures. 01/10/2014 - 30/09/2015

Abstract

Since the discovery of graphene, two-dimensional (2D) materials have attracted great attention mainly due to their unique physical properties and capability to fulfill the demands of future nanoelectronic industry on flexibility. Up to now various 2D monolayers have been synthesized experimentally, and they show many interesting features which are promising for technological applications such as field effect transistors, solar cells, and light emitting diodes. Combing different 2D materials into a single structure results in 2D heterostructures. 2D heterostrutures can have new properties different from the constituents, allowing the development of new devices in spintronics, optoelectronics and solar energy conversion. To achieve realistic applications, understanding and manipulating the electronic properties of 2D heterostructures is of importance. In this project, we investigate the effects of different factors, such as interface, composition of different materials and strain, on the properties of silicene/silicane superlattices and MX2 heterostructures. The aim is to provide theoretical guidance to tune the electronic and magnetic properties of 2D heterostructures.

Researcher(s)

Research team(s)

Spintronics with Transition metal Dichalcogenides. 01/01/2014 - 31/12/2014

Abstract

One of the aims of this project is to study possible implementations of the TMDs to the field of spintronics. The optimal single atomic layer TMD compounds for spintronics purposes will be searched. Next research topic in this project is to investigate TMDs based heterostructures.

Researcher(s)

Research team(s)

Electron correlations in bilayer and trilayer graphene. 01/10/2013 - 30/09/2016

Abstract

Many-body effects in multilayers of graphene and in coupled multilayers of graphene. Exciton superfluidity will be investigated in two coupled multilayers of graphene. The possibility of Wigner crystallization in such graphene layers will studied.

Researcher(s)

Research team(s)

Functionalization of graphene. 01/10/2013 - 13/07/2016

Abstract

This project represents a formal research agreement between UA and on the other hand Erasmus Mundus. UA provides Erasmus Mundus research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

Research team(s)

Superconductivity per atomic layer. 01/10/2013 - 30/09/2014

Abstract

In this project, we want to get theoretical insight in the effect of confinement and the choice of the substrate on the superconducting properties of atomically thin films by adding one monolayer at the time. In this respect, we aim to study elementary superconductors such as Pb and Sn, but also layered chalcogenides (such as NbSe2), and borides (MgB2, OsB2). The latter are particularly important being the most recently discovered (where MgB2 is the highest-temperature conventional (BCS theory) superconductor), while also being two-gap superconductors – where subtle interplay of two coupled Cooper-pair condensates leads to very rich physics.

Researcher(s)

Research team(s)

Chiral states of bilayer graphene in the presence of Rashba and intrinsic spin-orbit couplings. 01/10/2013 - 30/09/2014

Abstract

The aim of this project is to realize an analytically solvable model by deriving an effective Hamiltonian for the low-energy states of a BLG. We will assume that the system is in teh ballistic regime and will use the famous Landauer-Büttiker formula to study the charge and spin-dependent transport. In order to solve the effective Hamiltonian, at first we will look for an analytic solution. Subsequently, we will switch to find a numerical solution by using methods based on finite-difference of finite-elements; i.e., when we consider more complicated potential profiles. In this case we will employ a numerical solver such as COMSOL or MATLAB. Alternatively, we will write the Hamiltonian within a tightbindind model and use subsequently an exact numerical diagonalization approach.

Researcher(s)

  • Promotor: Peeters Francois
  • Co-promotor: Badalyan Samvel
  • Co-promotor: Massoud Ramezani Masir
  • Fellow: Shakouri Khosrow

Research team(s)

Self-Assembly of Patchy Particles for Nanotechnology Applications. 01/09/2013 - 31/08/2016

Abstract

We will build on our previous joint research on classical many-particle systems. Two fundamental extensions will be required in order to describe these novel systems: 1) the isotropic inter-particle interaction will now be generalized to anisotropic one with anisotropic particles. This implies that each particle will not only be characterized by its position but now also its orientation will be important resulting in a substantial increase of the degrees of freedom. 2) The hydrodynamic interaction with the fluidic environment will be incorporated increasing the complexity of the problem (and the computational challenges).

Researcher(s)

Research team(s)

Novel confinement-induced phenomena in superconducting nanograins. 01/09/2013 - 31/08/2015

Abstract

This project represents a formal research agreement between UA and on the other hand the Federal Public Service. UA provides the Federal Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

Research team(s)

Vibrational and electronic properties of superconducting films and nanoparticles investigated by advanced synchrotron and theoretical methods. 01/01/2013 - 31/12/2016

Abstract

In this project we aim to get a deeper understanding of the intimate link between the overall superconducting properties on one hand and the lattice dynamics of nanoscale systems on the other hand. We will approach this problem via new theoretical routes in conjunction with state of the art experiments.

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Research team(s)

Strain engineering of electronic correlations in graphene. 01/01/2013 - 31/12/2016

Abstract

The key questions we plan to answer in this project are: - How does strain affect electronic correlations? - Can one mechanically induce or manipulate magnetism in graphene? - Can different correlated states be stabilized through strain engineering?

Researcher(s)

Research team(s)

Theoretical study of fluctuations in unconventional superconductors. 01/10/2012 - 30/09/2015

Abstract

One of the main objectives is to develop efficient Monte Carlo methods, which can rigorously describe thermal (classical) phase fluctuations in unconventional superconductors. Although the core of these methods is generic, we will develop specific formulations for the different symmetries of the superconducting order parameters.

Researcher(s)

Research team(s)

Investigation of Novel Graphene-like Structures. 01/10/2012 - 30/09/2015

Abstract

The main objective of my project is to reveal electronic and magnetic properties of nanosized flat materials. The subject materials of the project are graphene and graphene-like structures. Graphene is made of carbon atoms that are one of the most abundant elements in the earth crust and it was shown earlier that it has many unique properties. Moreover graphene based materials are cheap and easier to integrate to existing technological applications. The results obtained in the scope of this project will be beneficial for future device applications. The developments of effective electronic device components, that are suitable for low-resistance and high mobility transport, are priorities in nanoelectronics research. I aim to extend the twodimensional playground created by graphene into a broader set of materials and discover new structures having new functionalities. Both in terms of theoretical and technological gain, the proposed work is very timely and relevant to today's science.

Researcher(s)

Research team(s)

The effect of strain on spin-orbit coupling in single- and multi-layer graphene. 01/10/2012 - 10/04/2015

Abstract

In this project we will investigate the spin-orbit interaction in graphene in the presence of in-plane and out-of-plane strain. By applying strain the interatomic distance changes and a rehybridization between different orbitals occurs. The key question which I want to answer is: how is the intrinsic and extrinsic spin-orbit coupling modified in the presence of strain? Therefore we will derive a modified Hamiltonian with spatial dependent spin orbit coupling. We will use this effective Hamiltonian to investigate several problems such as the quantum Hall states and edge states, spin polarization, quasi-bound states, topological insulator behaviour, valley and spin filtering. Such theoretical studies are important to complement and guide experimental work. The outcome of the present study will be different proposals how to manipulate in a controllable way (e. g. through strain) the spin-orbit interaction in single and multilayer graphene based systems.

Researcher(s)

Research team(s)

Tuning of the mechanical and electronic properties of graphene by strain, chemical doping and defects (MESCD). 01/07/2012 - 30/06/2014

Abstract

In this project we intend to focus on basic and advanced mechanisms that are potentially useful for controlling i) the strain distribution, ii) the band gap, iii) the observation and visualization of electronic polarization in single/multilayer graphene at the atomic scale.

Researcher(s)

Research team(s)

Computational modeling of materials (FWO Vis. Fel., Hasan SAHIN, Turky). 02/01/2012 - 31/12/2012

Abstract

Recent developments in synthesis and characterization of nanoscale materials have motivated theoretical work in exploring quantum effects at the nano-level. The aim of the project is to conduct theoretical research in order to identify and understand the fundamental physical mechanisms underlying the surface, interface and transport behavior of a variety of nanoscale materials using computational methods.

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Research team(s)

Nano-materials. 01/01/2012 - 31/12/2020

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

Research team(s)

Self-assembly of colloids with directional interaction. 01/01/2012 - 31/12/2015

Abstract

We plan to study the self-assembly of colloidal particles with directional interactions, i.e., Janus spheres and lock-and-key colloids, and address the kinetic growth of clusters, the influence of fluctuating membranes. Different aggregates will be investigated depending on the size of particles, the interaction strength, the number of species, etc.

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Interplay between atomic layers and functional adsorbates. 01/01/2012 - 31/12/2015

Abstract

Graphene is a non-magnetic, two-dimensional semimetal, which can be turned into an n- or p-type conductor by gate voltages. This results in unusually high charge carrier mobilities with mean free paths of several microns. The carriers follow a linear dispersion relation where the energy is proportional to the wave number, a behavior that is expected for massless particles. Within this project, we consider graphene in an electronic- and magnetic sense as a 'blank page', which will be modified by introducing defects, by adsorbed/implanted gas- or metal atoms, and by covalently bound atoms and chemical groups. We will monitor the evolution of the band-structure related, electronic and magnetic properties as a function of the type and density of these modifications. Hereby, theoretical modeling based on ab initio calculations and experimental analyses (conductivity, scanning probe microscopy in various forms, photocurrent spectroscopy) will go hand in hand. Special emphasis goes to the quest whether it is possible to achieve an 'engineered' band gap via targeted modifications: this would open broad applications from nanoelectronics to (bio-)chemical sensors. Analysis of deliberately induced defects includes also the mutual ordering of defects and the orientational ordering of adsorbants with respect to the underlying graphene layer.

Researcher(s)

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Electronic structure of modified graphene. 01/10/2011 - 30/09/2014

Abstract

The project deals with the theoretical characterization of functionalized graphene. Graphene is a recently (2004) discovered material with extraordinary electronic and mechanical properties. For some applications of graphene in nanothechnology it is important to change its properties. E.g. there is a problem for using graphene as the channel material in transistors because the conductivity of graphene always remains finite, i.e. the transistor can not be switched off. This problem can be overcome by functionalizing graphene, i.e. by the chemical attachment of atoms and molecules on a graphene surface. But functionalization is also important for other applications in e.g. biotechnology and spintronics. In this project I plan to investigate this functionalization by simulating it on an atomic level with theoretical models and examining the resulting changes in the electronic and mechanical properties.

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Interactions in composite graphene-based electronic systems. 01/10/2011 - 30/09/2012

Abstract

We focus on the analytical description of interacting electrons in novel quasi-onedimensional graphene-based systems: partially unzipped nanotubes and quantum spin Hall (QSH) edge states. Unlike their higher-dimensional counterparts, such systems often display Luttinger-liquid instead of Fermi-liquid behaviour, i.e. the fundamental excitations are not individual quasi-particles, but density waves that each can carry charge or spin.

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Visiting Postdoctoral Fellowship (Project 'Nanostructured and nonhomogeneous quantum wires'.)(BUDAGOSKY MARCILLA, Jorge Alejandro Marcilla, Spain) 01/05/2011 - 30/04/2012

Abstract

The aim of the project is to investigate theoretically the optical properties of GaN/InGaN core-shell nanowire structures. First the strain fields will be calculated including the piezoelectric potential. In the next step the electronic structure will be calculated by using the effective mass k.p-theory. The obtained band structure will be used to obtain the optical properties, i.e. optical absorption and excitonic effects.

Researcher(s)

Research team(s)

Electrical transport in nanostructures. 01/03/2011 - 31/08/2012

Abstract

This project represents a formal research agreement between UA and on the other hand the Federal Public Service. UA provides the Federal Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

Research team(s)

Nanoscale superconductivity: coherence and robustness of the superconducting state due to quantum confinement. 01/01/2011 - 31/12/2014

Abstract

The following open questions will be addressed in the project: How will the coherent properties of the pair condensate be modified in quantum-mechanically confined geometries? What about the robustness of the pair condensate against disorder in the presence of quantum confinement? How can quantum-size effects be influenced by phase fluctuations of the order parameter?

Researcher(s)

Research team(s)

Three-dimensional dynamics of coupled condensates in multiband and multilayered superconductors. 01/10/2010 - 30/09/2013

Abstract

The present project builds on the extensive experience and collaborations related to static and dynamic properties of superconductors accumulated in my first research mandate. However, very non-trivial extensions to my earlier numerical approaches must be developed for successful realization of this project.

Researcher(s)

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Spin-orbit and many-body interaction in semiconductor nanostructures. 01/09/2010 - 28/02/2012

Abstract

This project represents a formal research agreement between UA and on the other hand the Federal Public Service. UA provides the Federal Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

Research team(s)

Metal-insulator transitions in electron correlated systems. 01/01/2010 - 31/12/2013

Abstract

In this project, the goal is to induce a metal-insulator transition (MIT) in an oxide thin film, above room temperature, using a low voltage. There exists a broad range of materials that display a MIT, typically as a function of temperature or as a function of doping. The most prominent candidates for this study are compounds with strong electron correlation such as the cuprates, the manganates and the vanadates.

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CONGRAN: Confinement in Graphene Nanostructures. 01/01/2010 - 31/12/2012

Abstract

The qualitative goal of the project is to demonstrate and exploit the novel scientific possibilities of tunable gdots in comparison to conventional quantum dots defined in semiconductor heterostructures. We will investigate spin effects in the energy spectrum of gdots, the modified spin blockade in gdot systems and the transport properties of gdots under Coulomb blockade at elevated temperatures.

Researcher(s)

Research team(s)

Study of composite superconducting nanowires. 01/10/2009 - 30/09/2012

Abstract

The present project proposes to numerically solve the quantum mechanical mean-field equations describing superconductivity at a microscopic level. We will refine a novel method in order to consider various inhomogeneous situations: presence of impurities, surfaces, interfaces and/or magnetic fields. We will then apply this method to problems of interest related to nanoscale superconductivity.

Researcher(s)

Research team(s)

Nanostructured and nonhomogeneous quantum wires. 01/01/2009 - 31/12/2012

Abstract

The objective of this project is the theoretical study of the electronic properties of: - Lateral and radial nanostructured quantum wires. We will investigate the optical and transport properties. - Nonhomogeneous quantum wires. Study of effects due to geometrical fluctuations (i.e. lateral variations in the radius), of disorder, and of scattering on impurities and phonons on the electronic transport.

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Research team(s)

Nanostructured semiconductor/magnet/superconductor hybrids. 01/10/2008 - 30/06/2013

Abstract

Novel nanoscale phenomena in nano-engineered artificial semiconductor-magnet-superconductor hybrids will be studied theoretically. Different bi- and multi- component hybrid structures will be investigated, in search of improved functionalities of envisaged superconducting and spintronics devices. The proposed collaboration involves the Condensed Matter Theory group (UA) and the Institute for Theoretical Sciences (University of Notre Dame, USA).

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Research team(s)

(Self-)organization, dynamics and transport in finete systems. 01/10/2008 - 30/09/2011

Abstract

Objectives 1. Investigation of the effect of the finite size of the system. Study of crystallization, melting and glass formation. 2. Investigation of linear and non-linear dynamics of such systems under the influence of an external force. ¿ Linear: research of diffusion properties in a polydisperse system and the influence of the dimensionality of the system. ¿ Non-linear: Research of the influence of a fluid current on the colloidal particles or of another external force. The conditions for separation of between different particles in a polydisperse mixture will be investigated. The flow of particles in a monodisperse system in a pinning lattice will also be investigated.

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Research team(s)

Ab initio calculations of semiconductor nanowires. 01/10/2008 - 30/09/2010

Abstract

In this project we will perform ab initio total-energy calculations within the pseudopotential density-functional theory (DFT) on experimentally realized nanoclusters and nanowires. This approach allows us to study, on an atomic scale, the structure and electronic properties of these semiconducting nanocrystals.

Researcher(s)

Research team(s)

Graphene: Modeling of transport. 01/02/2008 - 15/07/2012

Abstract

This project represents a formal research agreement between UA and on the other hand a private institution. UA provides the private institution research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

Research team(s)

Center of excellence NANO. 01/01/2008 - 31/12/2014

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

Research team(s)

Nonlineair Dynamics in Nanosystems: Flux Quanta in Nanostructured Superconductors, Colloids, Nanocluster. 01/01/2008 - 31/12/2012

Abstract

Nanotechnology will be the technology of the 21st century. The major industrialized countries are comprehensively intensifying their research in material sciences with a focus on nanotechnology. Quantum-mechanical principles in nano-structured materials respresent one of the most exciting fields of modern physics. Nano-structured superconductors (NSSC) play a special role due tot the macroscopic quantum state of the superconducting charge carriers and the appearance of quantized flux lines (vortices), which develop in the presence of a magnetic field. The proposed research is devoted to the in-depth study of the nonlineair dynamics of flux qaunta in NSSC and includes several related and interdisciplinary topics. Main targets are: -Implementation of new approaches to study the nonlineair dynamics of flux quanta in NSSC. Creation of new efficient ways to control the flux motion and critical parameters of NSSC. -Understanding of the nonlineair dynamics of antivortices in NSSC. Elaboration of a proposal for their dynamical experimental verification. -Understanding and calculation of the behavious of the critical temperature on the size and shape of superconducting nanograins. -Study of the nonlineair dynamicq and the principles of self-assembly of colloidal binary mixtures. -Understanding of the growth kinetics of nanoclusters, influence of the environment, surface formation, etc.

Researcher(s)

Research team(s)

Polydispersivity and anisotropy in static and driven quasi-one and two dimensional systems. 01/01/2008 - 31/12/2011

Abstract

To understand the controlling parameters that determine order in polydispersive infinite quasi-one and twodimensional strongly correlated systems consisting of classical constituents. Study of crystallization, glass formation and melting. Investigation of the transition from ID to 2D. Study of the linear and nonlinear dynamics of such systems when driven by an external force. Linear: normal modes (i.e. phonons) and the effect of dimensionality and inter-particle interaction (i.e. correlation) on diffusion. Non-linear: motion in the presence of obstacles or through constrictions. We will address issues such as pinning, depinning and jamming of the strongly correlated polydispersive system.

Researcher(s)

Research team(s)

Nano-scale and low-dimensional correlated systems. 01/12/2007 - 31/12/2012

Abstract

Theoretical study of correlation effects in classical and quantum systems as e.g. low dimensional systems consisting of colloids, dusty plasma and nanostructures made of superconductors and graphene. Teams of complementary expertise in computational techniques and a common interest in multidisciplinary subjects are brought together.

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Research team(s)

Static and dynamic vortex matter in nanostructured type-I and type-II superconductors. 01/10/2007 - 30/09/2010

Abstract

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Controlling the Critical Parameters and Flux Motion in Nanostructured Superconductors. (CFNANOSC) 01/07/2007 - 30/06/2009

Abstract

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Quantum effects in clusters and nanowires. 01/01/2007 - 31/12/2011

Abstract

This project represents a formal research agreement between UA and on the other hand the Federal Public Service. UA provides the Federal Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

Research team(s)

Structural and electronic properties of biologically modified graphene-based layers. 01/01/2007 - 31/12/2010

Abstract

Aims of the research project: (i) to optimize the preparation and patterning of graphene-based layers to which biomolecules are attachted and (ii) to understand the magnetotransport properties of such layers in a wide temperature range before and after attaching the biomolecules. The results of these investigations will be applied to develop a sensitive electronic monitoring of specific biological processes in a liquid environment, including the denaturation and rehybridization of DNA molecules, and the sensing of immunoglobulin and immunoglobulin-antigen binding.

Researcher(s)

Research team(s)

Hybrid nanostructured superconductors. 01/01/2007 - 31/10/2007

Abstract

The vortex state in mesoscopic and nanostructured superconductors will be investigated when a superconductor is combined with a magnetic material. The approach will be based on a self-consistent solution of the Ginzburg-Landau equations through the method of simulated annealing.

Researcher(s)

Research team(s)

Structural and dynamical properties of fullerene hybrid systems: molecules in carbon nanotubes, cubane-fullerene mixed crystals, dynamics of a fullerene quantum gyroscope. 01/10/2006 - 30/09/2009

Abstract

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Modelling of nanostructures and classical clusters. 01/10/2006 - 30/09/2008

Abstract

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Research team(s)

Ab initio calculations of semiconductor nanocrystals: wires and clusters. 01/10/2006 - 30/09/2008

Abstract

In this project we will perform ab initio total-energy calculations within the pseudopotential density-functional theory (DFT) on experimentally realized nanoclusters and nanowires. This approach allows us to study, on an atomic scale, the structure and electronic properties of these semiconducting nanocrystals.

Researcher(s)

Research team(s)

FWO Visiting Postdoctoral Fellowship. (Pawel REDLINSKI, Poland) 01/10/2006 - 30/09/2007

Abstract

Study of the electronic properties of quantum wires using k.p-theory. Study of the exciton properties.

Researcher(s)

Research team(s)

Nanoscale condensate and flux confinement in superconductors. 01/01/2006 - 31/12/2009

Abstract

Two main important new topics will be focussed upon : - nanoscale evolution of Tc and gap in individual 3D structures; - controlling vortex patterns and achieving vortex manipulation in superconductors and S/F hybrids with nanoscale pinning centers and magnetic field techniques.

Researcher(s)

Research team(s)

High-precision reliable floating-point arithmetic and nanotechnology. 01/01/2006 - 31/12/2009

Abstract

Virtually all present-day computer systems, from personal computers to the largest supercomputers, implement the IEEE 54-bit floating-point arithmetic standard, which provides 53 binary or approximately 15 decimal digits accuracy. For most scientific applications, this is more than sufficient. However, for a rapidly expanding body of applications, 54-bit IEEE arithmetic is no longer sufficient. These range from some interesting new mathematical investigations to large-scale physical simulations performed on highly parallel supercomputers. Moreover in these applications, portions of the code typically involve numerically sensitive calculations, which produce results of questionable accuracy using conventional arithmetic [3]. These inaccurate results may in turn induce other errors, such as taking the wrong path in a conditional branch. Such blocks of code benefit enormously from a combination of reliable numeric techniques and the use of high-precision arithmetic. Indeed, the aim of reliable numeric techniques is to deliver, together with the computed result, a guaranteed upper bound on the total error or, equivalently, to compute an enclosure for the exact result. It is perhaps not a coincidence that interest in high-precision computations has arisen in the same period that many scientific computations are implemented on highly parallel and distributed, often heterogeneous, computer systems. Such systems have made possible much larger-scale runs than before, greatly magnifying numerical difficulties. Switching from hardware to high-precision arithmetic to tackle these difficulties, has benefits in its own right. Since high-precision arithmetic is implemented in software, the result is independent of the specific hardware in the heterogeneous system on which it is computed. In [3] the successful solution of several problems in scientific computing using high-precision arithmetic is described. It is worth noting that all of these successful applications of high-precision arithmetic have arisen in the past ten years. This may be indicative of the birth of a new era of scientific computing, in which the numerical precision required for a computation is as important to the program design as are the algorithms and data structures. Aim of the project It is the aim of the project team to contribute to the solution of a number of open problems in computational physics, in particular nanotechnology, which require the use of high-precision and reliable computations. The nanoscopic domain is a scale of length situated between the microscopic (atom and molecular scale) and the macroscopic scale. Characteristic for nanotechnology research is that a finite number (on the order of 10 to 10000) of particles (e.g. atoms, molecules, electrons) are involved, and hence that surface effects are of crucial importance. The large number of particles implies that it is practically impossible to obtain analytic results and that one needs to focus on computational methods. As will become clear from the project description, the key to the solution of the open problems in nanotechnology is the high-precision, reliable evaluation of certain special functions. Up to this date, even environments such as Maple, Mathematica, MATLAB and libraries such as IMSL, CERN and NAG offer no routines for the reliable evaluation of special functions.

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    Understanding materials at the (sub)nano level scale. 01/01/2006 - 31/12/2007

    Abstract

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    Strongly Coulomb coupled particle transport in plasmas and on solid substrates. 01/01/2006 - 31/12/2007

    Abstract

    This project belongs to the area of strongly correlated classical Coulomb systems. In the proposed project we will concentrate on: 1) strongly Coulomb correlations of dusty particles in a plasma environment, and 2) the deposition of such dusty particles on solid substrates.

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    Calculations of strain in materials under stress using the finite element method. 01/01/2006 - 31/12/2007

    Abstract

    The calculation of stress and strain is not only important in engineering problems, but also in self-organised quantum dots. In this project, we wish to calculate the strain in self-organised quantum dots with complex geometries and compositions using the elasticity theory, as used by engineers. The calculations will be done using the finite element method which is the popular method for engineers. The results will be used as input for electronic structure calculations for self-organised quantum dots.

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    Controlling the critical parameters in superconductors : nanograins, clusters and pinning arrays. (V. MISKO, Moldavië) 01/01/2006 - 31/03/2007

    Abstract

    Nanostructured superconductors play an important role in nanoscience since they provide a unique opportunity to apply quantum-mechanical principles to obtain specific superconducting properties needed for applications, by using nanoscale confinement of the condensate and flux to modify and control the coherent quantum ensembles of correlated eIectrons or holes responsible for the appearance of superconductivity. Designing specific material properties through the application of quantum mechanical principles is "quantum design" - a key idea in nanoscience. Superconductors, with their inherent quantum coherence over even macroscopie scale are in that respect superior to semiconductors, magnetic or normal metallic nanomaterials, where quantum coherence is much more difficult to achieve. In that respect nanostructured superconductors is the best choice for the demonstration of applicability of quantum design to tailor specific properties of materials at nanoscale. The two key properties: the absence of resistance to the dc current flow and quantum coherence of the condensate make superconductors extremely promising materials for nano-technologies and for various applications in micro- and nano-electronics, electrotechnics and as ultra-sensitive field, current and voltage sensors. Due to an intrinsic coherence of the condensate, superconducting eIements are primary candidates for developing physical realizations of the qubits for quantum computing. The possibiIities of the practical applications of superconducting materials, however, are limited by their critical parameters: temperature, field, and current. Remarkably, superconductors are materials where an artificial nanoscale modulation cao drasticalIy improve their critical parameters. In this project, we wilI study the size dependence of the superconducting properties and the critical parameters and we wilI investigate the electron pairing correlations at the nanometer scale.

    Researcher(s)

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    Properties of dilute magnetic semiconductor quantum dots. 01/01/2006 - 31/12/2006

    Abstract

    The aim of the project is to study the interaction between electrons and magnetic ions, in particular Mn ions, in semiconductor quantum dots. A small number of Mn ions is placed in a quantum dot. The electronic properties will depend on the interaction with the magnetic ions, but also on the position of the ions in the system. A theoretical study on the magnetic and optical properties of such a new type of nanostructure will be performed.

    Researcher(s)

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    Ab initio calculations of semiconductor nanocrystals: wires and clusters. 01/10/2005 - 30/09/2006

    Abstract

    In this project we will perform ab initio total-energy calculations within the pseudopotential density-functional theory (DFT) on experimentally realized nanoclusters and nanowires. This approach allows us to study, on an atomic scale, the structure and electronic properties of these semiconducting nanocrystals.

    Researcher(s)

    Research team(s)

    Theoretical study of two- and three-dimensional mesoscopic superconducting structures. 01/10/2005 - 31/08/2006

    Abstract

    The aim of the project is to give a theoretical description of the effects in mesoscopic superconducting structures of submicron dimensions.

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    Theory and modeling for nano-technology. 01/04/2005 - 31/03/2009

    Abstract

    Theoretical study of the mesoscopic physics governing the electronic and electro-optical properties as well as the electronic transport characteristics of low-dimensional semiconductors or metallic structures that may act as the active areas of future nanodevices.

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    Electronic properties of semiconductor quantum wires and quantum rings. 01/01/2005 - 31/12/2008

    Abstract

    The objective of this project is the theoretical study of the electronic properties of quantum wires and quantum rings.

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    Computer modeling of nanosystems. 01/01/2005 - 31/12/2007

    Abstract

    Modeling of semiconductor nanowires and superconductor nanostructures. Optical and electrical properties of nanowires will be investigated for sensor applications. Ab initio calculations of the electronic structure of nano-systems. Three dimensional meso- and nano-superconductors will be investigated, respectively within the Ginzburg-Landau approach and the Richardson formalism.

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    Spin polarization effects in diluted magnetic semiconductors (spin-DMS). 01/01/2005 - 31/12/2006

    Abstract

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    Self-assembled semiconductor nanostructures for new devices in photonics and electronics. (SANDIE) 01/07/2004 - 30/06/2008

    Abstract

    This is a Network of Excellence dedicated to the formation of an integrated and cohesive approach to research and knowledge in the field of self-assembled semiconductor nanostructures. These nanostructures can then be cemented in position by the deposition of further layers of the substrate material. By varying the semiconductor materials involved, the growth conditions, and by vertically stacking layers of nanostructures, a rich variety of novel materials can be produced for the study of the fundamental properties of strongly confined systems, and for the development of advanced electronic and optoelectronic devices.

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    Wigner Phase in Quantum Dots. 01/07/2004 - 30/06/2005

    Abstract

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    Phase coherence in quantum dots. (FWO Vis.Fel., Alexei Vagov) 01/02/2004 - 31/12/2004

    Abstract

    Investigation of the mechanisms which are responsible for the loss of phase coherence in quantum dots. In order to be able to use quantum dots as qubits it is essential that the phase coherence is as large as possible and that one is able to diminish those mechanisms which contribute to phase decoherence.

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    Hybrid systems on nanometerstructures. 01/01/2004 - 31/12/2008

    Abstract

    Research community between different flemish, wallons and non-Belgian laboratories. The following research subjects will be studied: study of metallic clusters; magnetic properties of nanostructures, spin dependent scattering; optical properties; study of two dimensional electron gas and quantum dots; theoretical modeling of nanostructures.

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    Structure, phases and evolution far from equilibrium in classical systems with a finite numer of degrees of freedom. 01/01/2004 - 31/12/2007

    Abstract

    Three systems will be studied: 1) particles with atttractive forces, 2) particles with repulsive forces and confinement, and 3) negative mobility in Coulombsystems. Ginzburg-Landau densityfunctional theory and Monte Carlo simulations in combination with a gradient method will be used.

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    Spin Polarization Effects in Semiconductors with Arrays of Magnetic Ions and Clusters. 01/01/2004 - 31/12/2007

    Abstract

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    Supercomputing cluster. 01/01/2004 - 31/12/2006

    Abstract

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    Confinement effects in nanostructured superconductors. 01/01/2004 - 31/12/2005

    Abstract

    In this research project the confinement phenomena of the magnetic flux and of the superconducting condensate (order parameter ?) will be investigated. On one hand we will focus on the finite geometrical confinement in small individual superconducting islands with different shapes (disc, square, triangle, line), where the effects of confinement on ? and the interaction between a little amount of flux lines will be studied. On the other hand the flux confinement will be realized in systems with a lattice of controlled artificial pinning centers, such as holes (antidots) or magnetic dots. Theoretically as well as experimentally there have already been significant efforts focused on the optimization of the flux pinning on defects of different types and measurements. By systematically varying the measurements, the geometry, the type and the distribution of the pinning centers, the conditions for optimized pinning and critical parameters will be studied.

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    Electron correlations in nanostructures : classical and quantum systems. 01/10/2003 - 30/09/2006

    Abstract

    In this project we study the effects of electron correlations in quantum mechanical as well as classical systems. In the quantum mechanical part of this project, the current research in the electronic properties of quantum dots and coupled quantum dots will be continued and extended to multi-excitons and wires. In the classical part we study dynamical properties of classical clusters using molecular dyunamics simulation techniques.

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    Spin effects in nanostructured semiconductors. (Balazs MOLNAR, Hongarije) 01/07/2003 - 30/06/2004

    Abstract

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    Canadian European Research Initiative On Nanostructures - 2. (CERION 2) 01/12/2002 - 31/05/2004

    Abstract

    This is the renewal of CERION. Its main purpose is the exchange of researchers and the organization of joint workshops. The University of Antwerp will collaborate with Prof. Vasilopoulos (Montreal) and Dr. Hawrylak (NRC, Ottawa).

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    Theoretical study of mesoscopic superconducting structures. 01/10/2002 - 30/09/2005

    Abstract

    The aim of the project is to give a theoretical description of the effects in mesoscopic superconducting structures of submicron dimensions.

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    Dynamical response of mesoscopic superconductors on an applied magnetic field and/or transport current. (Denis VODOLAZOV, Rusland) 15/09/2002 - 14/09/2003

    Abstract

    Vortex entry and exit in closed double connected mesoscopic superconducting systems with finite width will be investigated using the Ginzburg-Landau theory. A time-dependent analysis will be made using the time-dependent coupled non-linear Ginzburg-Landau equations. Ring and wire-like structures will be considered.

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      Theoretical research on charge correlation in low dimensional systems. 01/02/2002 - 31/01/2006

      Abstract

      Training in the physics of strongly correlated systems. Quantum as well as classical dots and molecules, colloids, dusty plasmas, ' are studied. Training in numerical techniques, finite difference methods, Monte Carlo and molecular dynamics simulations, density functional and Hartree-Fock theory.

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      Structure and dynamics of vortices and charged particles in mesoscopic confined systems. 01/01/2002 - 31/12/2007

      Abstract

      Theoretical study of thermodynamic properties and time dependent phenomena in confined mesoscopic systems. Investigation of the driving forces behind ordering. The aim is to find the underlying principles governing order and melting in different two-dimensional experimental realizable systems.

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      Mesoscopic and nanascopic superconductors. 01/01/2002 - 31/12/2002

      Abstract

      Study of confinement effects on the vortex structure in superconductors using the Ginzburg-Landau theory. Topics which will be studied are: boundary driven phase transition; systems out of thermodynamic equilibrium; nanoscopic superconductors.

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        Spintronics. 17/12/2001 - 17/12/2004

        Abstract

        We will study the quantum mechanical principles underlying spintronics. Spin dependent tunneling, spin coherence and spin injection will be investigated.

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        Correlations in Coulomb-interacting systems. 17/12/2001 - 17/12/2004

        Abstract

        In this project a number of topics will be studied. DFT will be extended towards the description of excited states and perfectly N-representable density matrices. In order to contribute to the understanding of optical properties of semiconductor systems, correlation effects on exitons and spin transport in heterostuctures will be studied. The influence of magnetic effects on clusters of 3d transition metal atoms will shed light on long-range coulomb behaviour. In an assessment of the performance of certain DFT functionals a number of calculations on molecules and clusters of interest to the farmaceutical industry as well as the nano-technology sector will be performed.

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        Many-body effects in the dynamical properties of bilayer electron systems. 01/12/2001 - 30/11/2003

        Abstract

        This is a Marie Curie postdoctoral fellowship for Dr. Egidijus Anisimovas. Strongly interacting electrons in confined and extended bilayers will be studied where many-body effects are important and where a description beyond the mean field level is needed.

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        Optical properties of nanostructured semiconductors. 01/10/2001 - 30/09/2005

        Abstract

        Study of Coulomb correlated electron-hole systems, i.e. exciton complexes. It will be investigated what is the influence of: the dimensionality of the superconducting system; the shape of the confinement; the interaction with the phonon modes of the semiconductor, and the influence of an external field.

        Researcher(s)

        Research team(s)

        Self-assembled nanostructured materials for electronic and optoelectronic applications (NANOMAT). 01/10/2001 - 30/09/2004

        Abstract

        Researcher(s)

        Research team(s)

        Electronic and optical properties of self-organized quantum dots. 01/10/2001 - 30/04/2002

        Abstract

        Study of the bandstructure of the electron and hole states in self-organized quantum dots. Effects due to the strain fields will be included. Valence and conduction bands will be calculated using the 6x6 k.p multiband theory. The theoretical results will be applied to the InP/InGaP system.

        Researcher(s)

        Research team(s)

          FWO Visiting Postdoctoral Fellowship. (Denis Vodolazov) 15/09/2001 - 14/09/2002

          Abstract

          Study of time dependent phenomena in nano-structured superconductors. Numerical solution of the time-dependent Ginzburg-Landau equations. Study of the penetration and exit of vortices.

          Researcher(s)

          Research team(s)

            Magneto-optical studies of exciton complex es and quantum mechanical coupling for improved quantum dot laser design. 01/08/2001 - 31/07/2005

            Abstract

            As primary components in fibre-optic telecommunication networks and optical data storage (CD), semiconductor lasers are an essential part of this information revolution. In this project we will study the magneto-optical properties of self-assembled quantum dots. Our goal is to support theoretically the experiments that exploit the effects of quantum mechanical coupling in order to improve their performance as lasers.

            Researcher(s)

            Research team(s)

            Optical properties and energy relaxation of self-assembled quantum dots and coupled quantum dots. 01/01/2001 - 31/12/2002

            Abstract

            Theoretical study of the optical properties of self-assembled quantum dots and vertically coupled quantum dots. The exciton energy, the diamagnetic shift and the recombination transition matrix element of those systems will be calculated as well as those of multi-exciton complexes. In a second stage the energy relaxation of these devices will be studied. The theoretical results will be compared with the PL-measurements in high magnetic fields which are done at the Laboratory of Solid State and Magnetism of KULeuven.

            Researcher(s)

            Research team(s)

              Study of the properties of charge carriers in low dimensional structures. Quantum Hall effect, electron-phonon interaction, transport, polarons and superconductivity 01/10/2000 - 30/09/2009

              Abstract

              The aim of the project is a theoretical study of the properties of charge carriers in structures of reduced dimensionality consisting of semiconductors or the high temperature superconductors

              Researcher(s)

              Research team(s)

              Surface electrons on mesoscopic structures. 01/10/2000 - 30/09/2004

              Abstract

              This is an EU-network which consists of a collaboration between 5 labs from the following countries: Belgium, England, France and Germany. The network is coordinated by F. Peeters. Experimental and theoretical research will be performed on novel mesoscopic structures from free electrons constrained to a structured surface of liquid helium. The interplay between electron correlation, confinement and the degree of quantum degeneracy will be studied.

              Researcher(s)

              Research team(s)

              Theoretical study of electon correlation in classical and quantum dots in strong magnetic fields. 01/10/2000 - 30/09/2003

              Abstract

              Electron correlation in quantum dots and in coupled quantum dots will be studied in the presence of an external magnetic field. The dynamics of the Wigner crystal will be studied. Quantum dots in the fractional quantum Hall regime will be studied and the interplay of this state with the Wigner solid will be investigated. Excitons in such quantum dots will also be studied.

              Researcher(s)

              Research team(s)

                Energy relaxation in quantum dots. 01/10/2000 - 30/06/2001

                Abstract

                Theoretical study of the energy relaxation in quantum dots and in coupled quantum dots. The effect of the phonon bottleneck effect on the energy relaxation. Study of phonon scattering in systems of reduced dimensions.

                Researcher(s)

                Research team(s)

                  Optical properties of low dimensional semiconductor nanostructures. 01/09/2000 - 31/08/2001

                  Abstract

                  The aim of the study is to provide theoretical support to the optical experiments on low dimensional semiconductor systems, and in particular on quantum dots and coupled quantum dots, which are currently performed (mainly at KUL) in the present IUAP.

                  Researcher(s)

                  Research team(s)

                    Vortex matter in nanostructured low dimensioal superconductors 01/02/2000 - 31/07/2000

                    Abstract

                    Study of the effect of confinement in nanostructured low dimensional superconductors on the flux pinning, the order parameter, and the interaction between the trapped flux lines using a numerical solution of the coupled Ginzburg-Landau equations.

                    Researcher(s)

                    Research team(s)

                      Electronic transport in low dimensional semiconductor nanostructures. 01/02/2000 - 31/07/2000

                      Abstract

                      Linear and non-linear ballistic transport in semiconductor structures. Study of asymsetric devices with artificial scatteringcenters.

                      Researcher(s)

                      Research team(s)

                        Mesoscopic and nanophysics of semiconductors and superconductors 01/01/2000 - 31/12/2003

                        Abstract

                        Theoretical study of the transport properties of mesoscopic systems and artificial nanostructures consisting of semiconductors and superconductors. Central in this study is that those systems consist of a finite number of degrees of freedom.

                        Researcher(s)

                        Research team(s)

                        Confinement phenomena in nanostructured superconductors. 01/01/2000 - 31/12/2003

                        Abstract

                        In this research project the confinement phenomena of the magnetic flux and of the superconducting condensate (order parameter ?) will be investigated. On one hand we will focus on the finite geometrical confinement in small individual superconducting islands with different shapes (disc, square, triangle, line), where the effects of confinement on ? and the interaction between a little amount of flux lines will be studied. On the other hand the flux confinement will be realized in systems with a lattice of controlled artificial pinning centers, such as holes (antidots) or magnetic dots. Theoretically as well as experimentally there have already been significant efforts focused on the optimization of the flux pinning on defects of different types and measurements. By systematically varying the measurements, the geometry, the type and the distribution of the pinning centers, the conditions for optimized pinning and critical parameters will be studied.

                        Researcher(s)

                        Research team(s)

                        Theoretical study of Hall sensors and non-linear transport of mesoscopic semiconductor structures 01/01/2000 - 30/09/2000

                        Abstract

                        Linear and non-linear electrical transport will be studied in Hall sensors in the presence of a nonhomogeneous magnetic field. The influence of the shape of the Hall sensor and the presence of asymmetric scatterers on the output of the device will be studied.

                        Researcher(s)

                        Research team(s)

                          Theoretical study of magnetic clusters in semiconductors. 01/10/1999 - 30/09/2001

                          Abstract

                          Investigation of the properties of magnetic clusters in doped semiconductor structuren. Hybrid ferromagnetic/semiconductor Hall devices. Spin dependent transport.

                          Researcher(s)

                          Research team(s)

                            Fundamental study of non-homogeneous magnetic fields in nano-electronics. 01/10/1999 - 30/06/2000

                            Abstract

                            Study of hybrid semiconductor structures. Manipulation of the electron motion using non-homogeneous magnetic fields. New electron states in quantum wires.

                            Researcher(s)

                            Research team(s)

                              Spin correlations and spin dependent transport in high magnetic fields. 01/01/1999 - 31/12/2003

                              Abstract

                              To obtain a deeper insight into the problem of spin correlations and the role of mobile charge carriers in transferring the spin orientations. This will be done by incorporating individual localized magnetic moments and/or their clusters in semiconductors or diluted magnetic semiconductors or semi-magnetic semiconductors. Study of spin dependent scattering of mobile charge carriers in "Giant" and "Colossal" magnetoresistance.

                              Researcher(s)

                              Research team(s)

                              Nanostructures: electronic, magnetic, and optical phenomena. 01/01/1999 - 31/12/2003

                              Abstract

                              Research community between different flemish, wallons and non-Belgian laboratories. The following research subjects will be studied: study of metallic clusters; magnetic properties of nanostructures, spin dependent scattering; optical properties; study of two dimensional electron gas and quantum dots; theoretical modeling of nanostructures.

                              Researcher(s)

                              Research team(s)

                              Electronic transport in quantum wires and quantum dots. 21/12/1998 - 22/12/2001

                              Abstract

                              A theoretical study will be made of the fundamental mechanisme which govern the electronic transport propertjes of low-dimensional semiconductor structures. Due to the increased miniaturization the electron motion in future semiconductor devices is reduced to smaller length scales were the laws of quantum mechanica govern the behavior of electrons. This requires different theoretical approaches as compared to previous micro-systems where the electron motion is still classical and only the scattering mechanisms will be quantum mechanical. In future nano-electronic systems, or sub-micron devices, also the electron motion has to be treated quantum mechanically. Such systems are, and will be, important for future micro-electronics and electro-optical devices. In this project we will study a subclass of systems which consists of quantum wires and quantum dot systems. Fundamental aspects related to electronic transport in those systems will be investigated theoretically. The different teams involved in the present project have complemenlary knowledge which will be relevant to realize the present study.

                              Researcher(s)

                              Research team(s)

                                Density functional theory and properties of complex systems. 21/12/1998 - 22/12/2001

                                Abstract

                                Density Functional Theory (DFT) has been well established for a long time, and within the framework of the Local Density Approximation (LDA) it has been successfully applied to atoms, molecules, solide (2D as well as 3D), surfaces, polymers, etc. Up till now deficiencies within this approximation can be reduced by the use of Gradient Corrected functionals (GGA) which seem to have a sizeable effect on molecules, less in solide, while in polymers it still remains to be investigated. Other means of improvement of the LDA are the Optimized Effective Potential (OEP), Many Body Perturbation methode (MBPT), density functionals for excited states, nonlocal density functionals based on pair-correlation functionals and Wigner-functions have recently been developed, but have only been applied to relatively simple systems. Despite the need for further improvements LDA is still an outstanding tool to investigate the properties of complex systems and the mechanism of physical phenomena. The different teams involved in the present project have complementary background (chemistry, physics) and are working on complementary systems (atoms, molecules, polymers, semiconductors, biopolymers) using the DFT teelmique.The present proposal aims to extend the existing collaboration and the complementarity in knowledge will be important to realize the present study.

                                Researcher(s)

                                Research team(s)

                                  Flux trapping in superconducting structures of reduced dimensions 01/12/1998 - 30/11/1999

                                  Abstract

                                  Theoretical study of the flux configurations in mesoscopic superconducting systems. Influence of the boundary on the symmetry of the vortex configurations. Study of the giant and multi-vortex transition.

                                  Researcher(s)

                                  Research team(s)

                                    Optical properties and energy relaxation of self-assembled quantum dots and coupled quantum dots. 01/10/1998 - 30/09/2000

                                    Abstract

                                    Theoretical study of the optical properties of self-assembled quantum dots and vertically coupled quantum dots. The exciton energy, the diamagnetic shift and the recombination transition matrix element of those systems will be calculated as well as those of multi-exciton complexes. In a second stage the energy relaxation of these devices will be studied. The theoretical results will be compared with the PL-measurements in high magnetic fields which are done at the Laboratory of Solid State and Magnetism of KULeuven.

                                    Researcher(s)

                                    Research team(s)

                                      Artificial atoms : structure and energy relaxation. 01/10/1998 - 30/09/2000

                                      Abstract

                                      Theoretical study of the properties of artificial atoms in semiconductor nanostructures. Investigations of the correlations between the electrons and their energy relaxation.

                                      Researcher(s)

                                      Research team(s)

                                        Theoretical study of mesocopic superconducting structures. 01/10/1998 - 30/09/1999

                                        Abstract

                                        The aim of the project is to give a theoretical description of the effects in mesocopic superconducting structures of submicron dimensions.

                                        Researcher(s)

                                        Research team(s)

                                          Canadian-European research initiative on nanostructures (Cerion). 01/05/1998 - 30/04/2001

                                          Abstract

                                          The Cerion working group coordinate the research of 17 European and 8 Canadian nodes, actively participating in research on nano-electronics, nano-optics and the technology of advanced nano-structures.

                                          Researcher(s)

                                          Research team(s)

                                            Excitons in low dimensional semiconductors at high magnetic fields. (FWO Vis.Fel.) 01/02/1998 - 31/01/1999

                                            Abstract

                                            Researcher(s)

                                            Research team(s)

                                              Hybrid ferromagnetic-semiconductor structures. 01/12/1997 - 10/03/2001

                                              Abstract

                                              The project involves a collaboration between two theoretical groups (Antwerp and MontrÚal) and an experimental group at IMEC. We will study the modification of the electron motion due to the presence of ferromagnetic clusters in a semiconductor material.

                                              Researcher(s)

                                              Research team(s)

                                                Theoretical study of magnetic clusters in semiconductors. 01/10/1997 - 30/09/1999

                                                Abstract

                                                Investigation of the properties of magnetic clusters in doped semiconductor structuren. Hybrid ferromagnetic/semiconductor Hall devices. Spin dependent transport.

                                                Researcher(s)

                                                Research team(s)

                                                  Study of type-II semiconductor structuren: InAs/GaSb. 01/10/1997 - 30/09/1999

                                                  Abstract

                                                  Study of the electrical transport and optical properties of InAs/GaSb semiconductor structures. Investigation of cyclotron resonance alla magneto-transport in parallel magnetic fields. Study of the mobility as function of the gate voltage.

                                                  Researcher(s)

                                                  Research team(s)

                                                    Transport and scattering processes in non-homogeneous magnetic quantum structures of reduced dimensions. 01/10/1997 - 30/09/1998

                                                    Abstract

                                                    A theoretical study of the magnetotransport, optical and magnetic properties of hybrid semiconductor/ferromagnetid nanostructures will be performed.

                                                    Researcher(s)

                                                    Research team(s)

                                                      Nanophysics of superconductors. 01/09/1997 - 31/08/1998

                                                      Abstract

                                                      Investigation of the superconducting states in thin superconducting disks using the nonlinear Ginsburg-Landau equations. Calculation of the phase diagram for type I tot type II transitions and for the multivortex to giant vortex transition.

                                                      Researcher(s)

                                                      Research team(s)

                                                        Reduced dimensionality systems. 01/01/1997 - 31/12/2001

                                                        Abstract

                                                        Study of the mesocopic world in which the dimensions of the materials are smaller than a characteristic physical length scale and where new one and zero dimensional phenomena occur which are a consequence of the interference between the elctrons and the dimensional confinement of the system.

                                                        Researcher(s)

                                                        Research team(s)

                                                          Theory of confinement phenomena in submicron structures. 01/01/1997 - 31/12/2000

                                                          Abstract

                                                          The aim of the project is to provide a theoretical description, using methods of solid state physics and statistical physics of measurable effects and phenomena in confined inhomogeneous systems of submicron size.

                                                          Researcher(s)

                                                          Research team(s)

                                                            Study of the properties of charge carriers in low dimensional structures. Quantum Hall effect, electron-phonon interaction, transport, polarons and superconductivity 01/10/1996 - 30/09/2000

                                                            Abstract

                                                            The aim of the project is a theoretical study of the properties of charge carriers in structures of reduced dimensionality consisting of semiconductors or the high temperature superconductors

                                                            Researcher(s)

                                                            Research team(s)

                                                              Artificial atoms : structure and energy relaxation. 01/10/1996 - 30/09/1998

                                                              Abstract

                                                              Theoretical study of the properties of artificial atoms in semiconductor nanostructures. Investigations of the correlations between the electrons and their energy relaxation.

                                                              Researcher(s)

                                                              Research team(s)

                                                                Nanophysics of superconductors. 01/10/1996 - 30/06/1997

                                                                Abstract

                                                                Investigation of the properties of superconducting nanostructures, in particular of superconducting disks. Study of multi-flux structures.

                                                                Researcher(s)

                                                                Research team(s)

                                                                  Magnetophotoluminescence of semiconducting nanostructures in pulsed fields. 01/01/1996 - 31/12/2001

                                                                  Abstract

                                                                  Magnetophotoluminescence studies will be performed in order to investigate the confinement effects in GaAs/AlGaAs heterostructures, wires and quantum dots at low temperatures and in fields up to 60 Tesla.

                                                                  Researcher(s)

                                                                  Research team(s)

                                                                    Electrical transport in low-dimensional semi-conductor structures. 01/01/1996 - 31/12/2001

                                                                    Abstract

                                                                    The electrical transport, the optical and the magnetic properties of new ferromagnetic and semiconductor systems will be studied. The following systems will be investigated : (1) delta-layers in InSb 2) InAs/GaSb quantum systems 3) hybrid systems and 4) impurities and clusters in III-V semiconductors.

                                                                    Researcher(s)

                                                                    Research team(s)

                                                                      Artificial atoms : structure and properties. 01/10/1995 - 31/12/1996

                                                                      Abstract

                                                                      The structure and properties of systems consisting of a finite number of charged particles will be studied. Classical (eg. colloids, ions,) and quantum (eg. electrons) particles will be studied.

                                                                      Researcher(s)

                                                                      Research team(s)

                                                                        Magnetotransport in nanostructures. 01/10/1995 - 30/09/1996

                                                                        Abstract

                                                                        Theoretical study of the electrical conduction properties of nanostructures consisting of semiconductors in the presence of a strong magnetic field. Special emphasis will be on the magnetic freeze out of carriers.

                                                                        Researcher(s)

                                                                        Research team(s)

                                                                          Magnetic freeze-out and quantum effects in multilayers. 01/01/1995 - 31/12/1998

                                                                          Abstract

                                                                          Magnetic freeze out will be investigated in 1) 2D quantum wells of III-V semiconductors 2) diluted semimagnetic semiconductors and 3) titanium oxide thin films.

                                                                          Researcher(s)

                                                                          Research team(s)

                                                                            Magnetic freeze-out and quantum effects in multilayers. 01/01/1995 - 31/12/1996

                                                                            Abstract

                                                                            Magnetic freeze out will be investigated in 1) 2D quantum wells of III-V semiconductors 2) diluted semimagnetic semiconductors and 3) titanium oxide thin films.

                                                                            Researcher(s)

                                                                            Research team(s)

                                                                              Study of nanostructures consisting of ferromagnetic materials and semiconductors. 01/10/1994 - 30/09/1996

                                                                              Abstract

                                                                              Theoretical study of the ferromagnetic/semiconductor interface and transport through such an interface. Behaviours of conduction and valence bands. Investigation of spin injection through the interface.

                                                                              Researcher(s)

                                                                              Research team(s)

                                                                                Correlations in confined classical and quantum few body systems. 01/07/1994 - 31/12/1997

                                                                                Abstract

                                                                                Different physical systems consisting of a finite number of charged particles will be studied. Many particle effects like correlation and exchange will be investigated. We envisage to study : quantum systems and quantum dots; classical two dimensional atoms and clusters.

                                                                                Researcher(s)

                                                                                Research team(s)

                                                                                  Alternative silicide Si:Ge Schottky barriers as infrared detectors. 01/05/1994 - 31/05/1995

                                                                                  Abstract

                                                                                  Study of CoSi2, Co(SiGe)2 on Si:Ge. Investigation of optical and transport properties of this metal/semiconductor interface : infrared properties and tunnel current.

                                                                                  Researcher(s)

                                                                                  Research team(s)

                                                                                    Two-dimensional electron systems on cryogenic surfaces. 01/01/1994 - 31/12/1995

                                                                                    Abstract

                                                                                    This project is a HCM-network between 7 laboratories : Eindhoven, London, Grenoble, Saclay, Southampton, Antwerpen. It is coordinated by Prof. Leiderer of the University of Konstanz. The topic of this project is the study of a two-dimensional electron gas on liquid helium and other cryogenic surfaces.

                                                                                    Researcher(s)

                                                                                    Research team(s)

                                                                                      Electronic and magnetic properties of compound semiconductors in high magnetic fields. 01/01/1994 - 31/12/1994

                                                                                      Abstract

                                                                                      Study of the magneto-resistance and Hall effect in low dimensional semiconductor systems, like heterostructures, quantum wells, superlattices and delta-layers.

                                                                                      Researcher(s)

                                                                                      Research team(s)

                                                                                        Multi-subband electronic transport in systems of reduced dimensions. 01/10/1993 - 30/09/1995

                                                                                        Abstract

                                                                                        Electric properties of semiconductor heterostructures, delta layers and quantum wires based on III-V compounds will be studied. The project focuses on the theoretical study of these materials in the situation that they contain a high density of electrons such that several electric subbands are occupied.

                                                                                        Researcher(s)

                                                                                        Research team(s)

                                                                                          Metal-insulator transition in semiconductors. 01/10/1993 - 31/07/1994

                                                                                          Abstract

                                                                                          Determination of the parameters which govern the metal-insulator transition in semiconductor quantum wells and superlattices. Investigation of the influence of the magnetic field on this transition.

                                                                                          Researcher(s)

                                                                                          Research team(s)

                                                                                            Electron correlations and electron-phonon interaction in systems of reduced dimensions. Carriertransport in CuO2-planes. 01/01/1993 - 31/12/1994

                                                                                            Abstract

                                                                                            The project aims at the theoretical description of the electronic properties of the zero-dimensional electron gas in quantum dots, and of the two-dimensional electron gas in metallic films and superlattices, and in the CuO2 layers of the high-temperature superconductors.

                                                                                            Researcher(s)

                                                                                            Research team(s)

                                                                                              Study of fundamental problems in nanoelectronics. 01/01/1993 - 31/12/1993

                                                                                              Abstract

                                                                                              The aim of the project is to make a detailed study of the properties of charge carriers (electrons and holes) in structures of sub-micron dimensions. Examples of semiconductor structures which will be studied are : 1) double barrier structures 2) quantum wires 3) quantum dots 4) a lattice of anti-dots.

                                                                                              Researcher(s)

                                                                                              Research team(s)

                                                                                                Study of the properties of charge carriers in low dimensional structures. Quantum Hall effect, electron-phonon interaction, transport, polarons and superconductivity. 01/10/1992 - 30/09/1996

                                                                                                Abstract

                                                                                                The aim of the project is a theoretical study of the properties of charge carriers in structures of reduced dimensionality consisting of semiconductors or the high temperature superconductors.

                                                                                                Researcher(s)

                                                                                                Research team(s)

                                                                                                  Electrical transport in low dimensional semiconductor structures. 01/03/1992 - 31/12/1995

                                                                                                  Abstract

                                                                                                  Study of the electrical transport properties of the new semiconductor systems : 1) GaAs/Ga heterostructures and 2) ferro-magnetic films on semiconductor substrates.

                                                                                                  Researcher(s)

                                                                                                  Research team(s)

                                                                                                    Study of fundamental problems in nanoelectronics. 01/01/1992 - 31/12/1992

                                                                                                    Abstract

                                                                                                    The aim of the project is to make a detailed study of the properties of charge carriers (electrons and holes) in structures of sub-micron dimensions. Examples of semiconductor structures which will be studied are : double barrier structures; quantum wires; quantum dots; a lattice of anti-dots.

                                                                                                    Researcher(s)

                                                                                                    Research team(s)

                                                                                                      Electronic and magnetic properties of compound semi-conductors in ì high magnetic fieldsì 01/01/1991 - 31/12/1994

                                                                                                      Abstract

                                                                                                      Experimental and theoretical study of electronic and magnetic properties of compound III-V semiconductors, with a digression to II-VI semiconductors. Investigation of collective effects like the fractional quantum effect and Wigner crystallisation in GaAs-heterostructures and in quasi-one and quasi-zero dimensional structures by magneto-transport and magneto-optical experiments.

                                                                                                      Researcher(s)

                                                                                                      Research team(s)

                                                                                                        Electron correlations and electron-phonon interaction in systems ì of reduced dimensions. Carriertransport in CuO2-planes.ì 01/01/1991 - 31/12/1994

                                                                                                        Abstract

                                                                                                        The project aims at the theoretical description of the electronic properties of the zero-dimensional electron gas in quantum dots, and of the two-dimensional electron gas in metallic films and super lattices, and in the CuO2 layers of the high-temperature superconductors

                                                                                                        Researcher(s)

                                                                                                        Research team(s)

                                                                                                          01/08/1988 - 30/09/1992

                                                                                                          Abstract

                                                                                                          Researcher(s)

                                                                                                          Research team(s)