Piezoelectricity in asymmetrically strained bilayer graphene

Datum: 1 juni 2016

Locatie: University of Antwerp - Campus Groenenborger - Room U.241 - Groenenborgerlaan 171 - 2020 Antwerpen

Tijdstip: 15 - 16 uur

Organisatie / co-organisatie: Condensed Matter Theory

Korte beschrijving: Condensed matter seminar presented by Matthias Van der Donck

We study the electronic properties of commensurate faulted bilayer graphene by diagonalizing the one-particle Hamiltonian of the bilayer system in a complete basis of Bloch states of the individual graphene layers. Our novel approach is very general and can be easily extended to any commensurate graphene-based heterostructure. Here, we consider three cases: i) twisted bilayer graphene, ii) bilayer graphene where triaxial stress is applied to one layer, and iii) bilayer graphene where uniaxial stress is applied to one layer. We show that the resulting superstructures can have very different low-energy spectra depending on the twist angle or the magnitude and direction of the induced strain. For the cases of triaxial and uniaxial stress, the individual graphene layers tend to decouple and we find significant charge transfer between layers. In addition, this piezoelectric effect can be tuned by applying a perpendicular electric field.

Matthias Van der Donck, CMT UAntwerpen

Contact e-mail: lucian.covaci@uantwerpen.be

Link: http://cmt.uantwerpen.be