Long range Coulomb interaction in the ground state of bilayer graphene

TL;DR

This paper investigates how long-range Coulomb interactions influence the electronic ground state of bilayer graphene in magnetic fields, revealing their role in Landau level mixing and spin state changes.

Contribution

It demonstrates the significant impact of Coulomb interactions on Landau level mixing and spin configurations in bilayer graphene under magnetic fields.

Findings

Coulomb interactions cause Landau level mixing in unbiased bilayer graphene.

Interactions lead to a change in the total spin of the ground state in biased bilayer.

Long-range Coulomb effects are crucial for understanding bilayer graphene's electronic properties.

Abstract

We report on our studies of interacting electrons in bilayer graphene in a magnetic field. We demonstrate that the long range Coulomb interactions between electrons in this material are highly important. We show that in the unbiased bilayer (where both layers are at the same electrostatic potential), the interactions can cause mixing of Landau levels in moderate magnetic fields. For the biased bilayer (when the two layers are at different potentials), we demonstrate that the interactions are responsible for a change in the total spin of the ground state for half-filled Landau levels in the valence band.