Electrostatic interactions in twisted bilayer graphene

TL;DR

This paper investigates how long-range electrostatic interactions influence the electronic properties of twisted bilayer graphene, revealing their impact on band structures and the emergence of various symmetry-broken phases.

Contribution

It introduces a Hartree-Fock based analysis of electrostatic effects in twisted bilayer graphene, highlighting their role in band modifications and phase transitions.

Findings

Band widths and shapes depend strongly on electron filling.

Broken symmetry phases occur at multiple densities.

Valley/spin polarization and sublattice symmetry breaking are observed.

Abstract

The effects of the long range electrostatic interaction in twisted bilayer graphene are described using the Hartree-Fock approximation. The results show a significant dependence of the band widths and shapes on electron filling, and the existence of broken symmetry phases at many densities, either valley/spin polarized, with broken sublattice symmetry, or both.