Importance of interband transitions for the fractional quantum Hall effect in bilayer graphene

TL;DR

This paper investigates how interband transitions and polarization effects influence the stability of fractional quantum Hall states in bilayer graphene, showing significant modifications to phase diagrams beyond single Landau level approximations.

Contribution

It extends previous models by including interband transitions and polarization effects, providing a more accurate phase diagram for fractional quantum Hall states in bilayer graphene.

Findings

Interband transitions significantly alter phase stability.

Polarization effects modify the Pfaffian state's stability region.

Realistic dielectric constants impact the phase diagram.

Abstract

Several recent works have proposed that electron-electron interactions in bilayer graphene can be tuned with the help of external parameters, making it possible to stabilize different fractional quantum Hall states. In these prior works, phase diagrams were calculated based on a single Landau level approximation. We go beyond this approximation and investigate the influence of polarization effects and virtual interband transitions on the stability of fractional quantum Hall states in bilayer graphene. We find that for realistic values of the dielectric constant, the phase diagram is strongly modified by these effects. We illustrate this by evaluating the region of stability of the Pfaffian state.