Research team
Expertise
Expertise on quantum theory applied to nanoscale and nanoengineered materials, in view of their mechanical, electronic, magnetic and optical properties. The main methodology used is density functional theory (DFT), put to practice using highly parallelized computing. Current research activities mainly involve novel quantum states in two-dimensional materials, such as transition metal dichalcogenides, with a strong focus on collective electron behaviour, such as superconductivity. Here, the DFT results are combined with dedicated quantum field theories describing these collective quantum states. Furthermore, a strong experience on solar cell performance and other energy applications was built up over the years.
Heterostructures of superconducting 2D materials as building blocks for emerging quantum technologies
Abstract
Junctions of superconducting materials lay the basis for the newest quantum technologies, especially quantum computing (pursued by Google, IBM, Intel,...), with capabilities far beyond classical approaches. However, the needed quantum coherence is severely limited by impurities and roughness at the interfaces in currently fabricated junctions. To resolve this, crystalline 2D materials are explored as alternative building blocks for superconducting junctions, because of their high purity and atomically sharp interfaces in their heterostructures. However, fundamental understanding of how the superconducting state is affected by joining different 2D materials is still lacking. Therefore, a new ab initio framework will be developed in this project, fully characterizing superconductivity in 2D heterostructures in presence of interlayer hybridization and competing quantum phases. This will yield insight into key properties like distribution and quantum tunneling of Cooper pairs across the junction, which lie at the heart of qubit applications. Motivated by the most recent experiments, both vertical and lateral junction architectures will be considered, and optimized through the available degrees of freedom, like twisting and stacking order, use of a buffer material in the junction, and tuning the junction through gating or strain. Such accumulated knowledge is indispensable to further advance and control qubit characteristics and quantum operations based on 2D superconductors.Researcher(s)
- Promoter: Milosevic Milorad
- Fellow: Bekaert Jonas
Research team(s)
Project type(s)
- Research Project
Ionic transport and phase transitions in alkali-intercalated two-dimensional materials under active manipulation.
Abstract
Ionic transport in low-dimensional materials plays the key role in novel concepts of energy harvesting and storage devices. Recent experimental progress allowed fabrication of extremely narrow (comparable to the size of an atom, where quantum effects dominate) and clean channels between 2D materials that are weakly bound together. The flow of ions or molecules is such channels was found to be extremely swift, which was attributed to high pressure induced by such a tight confinement. This pressure also made atoms pack closer together and produce a completely different composite structure by forming bonds with the confining material. The narrowness of the channels allows only a few layers of atoms to move through, in a fashion tunable by applied pressure, lateral strain, or electric field. Once understood, the advanced ionic transport under quantum confinement has potential to boost performance and capacity of batteries. Furthermore, the bonding of ions to the confining material can completely change the electronic phase of the system, so that it becomes e.g. superconducting at low temperatures, and useful for dissipationless electronics. Therefore, the main objective of my project is to investigate the mechanisms of ionic flow in strongly confined channels, how to manipulate ionic ordering and flow therein, and to identify the emergent phase transitions in the systems of interest – to enable novel concepts for blue-energy, miniaturized battery, and nanoelectronics applicationsResearcher(s)
- Promoter: Milosevic Milorad
- Co-promoter: Bekaert Jonas
- Fellow: Petrov Mikhail
Research team(s)
Project type(s)
- Research Project
Transition metal dichalcogenides as unique 2D platform for collective quantum behavior.
Abstract
Two-dimensional transition metal dichalcogenides (2D-TMDs) are atomically-thin materials at the forefront of research, owing to their special electronic and optical properties, their tunability by electric gating and mechanical strain, and easy heterostructuring. It is much less explored that they also exhibit a wealth of collective quantum phases, characterized by a collective behavior of the electrons that is entirely different from their individual states. One such phase is a charge density wave, where electrons at lower temperatures form an ordered quantum fluid that restructures the host material. Another low-temperature collective quantum phase in 2D-TMDs is a superconducting one, where electrons condense into a resistance-less sea of Cooper pairs, that carries electric current without dissipation. Furthermore, the spins of the electrons add to the combinatorial possibilities for novel quantum states, and can form textures in monolayer TMDs that are wholly absent in the bulk. All these states are strongly intertwined, but the fundamentals of their interplay are not well understood – which hinders further progress towards novel functionalities and advanced applications. In this project, I will elucidate this interplay using state-of-the-art theoretical tools, and provide a roadmap to tailor it – by e.g. strain, gating and doping – in order to establish 2D-TMDs as a unique platform for highly versatile quantum devices, employing the advantages of all different states at play.Researcher(s)
- Promoter: Milosevic Milorad
- Co-promoter: Partoens Bart
- Fellow: Bekaert Jonas
Research team(s)
Project type(s)
- Research Project