PhysRevB.98.205151.pdf (1.11 MB)
Electronic phases in twisted bilayer graphene at magic angles as a result of Van Hove singularities and interactions
journal contribution
posted on 2018-11-13, 11:31 authored by Yury Sherkunov, Joseph BetourasJoseph BetourasThe discovery of different phases as a result of correlations, especially in low-dimensional materials, has been always an exciting and fundamental subject of research. Recent experiments on twisted bilayer graphene have revealed reentrant unconventional superconductivity as a function of doping as well as a Mott-like insulating phase when the two layers are twisted with respect to each other at certain “magic” angles for doping corresponding to two particles per moire unit cell. In this work we propose a microscopic model that takes into account interactions and the van Hove singularities in the density of states of the twisted bilayer graphene at doping corresponding to one particle (ν=1) per moir'{e} unit cell and study how superconductivity emerges. We identify the possible symmetry of the order parameter as s±, while if the inter-valley coupling is negligible the symmetry is s++. In addition, we find and characterise the insulating region of the system, as a region with a uniform charge instability where there is coexistence of the metallic and insulating phases.
Funding
This work was supported by the EPSRC through the grant EP/P002811/1.
History
School
- Science
Department
- Physics
Citation
SHERKUNOV, Y. and BETOURAS, J.J., 2018. Electronic phases in twisted bilayer graphene at magic angles as a result of Van Hove singularities and interactions. Physical Review B, 98 (20), 205151.Publisher
© American Physical SocietyVersion
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Publication date
2018-11-29Notes
This paper was published in the journal Physical Review B and is also available at https://doi.org/10.1103/PhysRevB.98.205151.ISSN
2469-9950eISSN
2469-9969Publisher version
Language
- en