Tuning equilibration of quantum Hall edge states in graphene - role of crossed electric and magnetic fields

TL;DR

This paper investigates how crossed electric and magnetic fields in graphene's quantum Hall regime affect edge state equilibration, revealing electric field-induced modifications to Landau levels and resulting in altered transport properties.

Contribution

It demonstrates the role of local electric fields in tuning edge state equilibration and Landau level modifications in graphene quantum Hall systems.

Findings

Lack of equilibration observed along electrostatically formed edge states.

High electric fields at interfaces modify Landau levels in graphene.

Electric field tuning affects scattering and longitudinal resistance.

Abstract

We probe quantum Hall effect in a tunable 1-D lateral superlattice (SL) in graphene created using electrostatic gates. Lack of equilibration is observed along edge states formed by electrostatic gates inside the superlattice. We create strong local electric field at the interface of regions of different charge densities. Crossed electric and magnetic fields modify the wavefunction of the Landau Levels (LLs) - a phenomenon unique to graphene. In the region of copropagating electrons and holes at the interface, the electric field is high enough to modify the Landau levels resulting in increased scattering that tunes equilibration of edge states and this results in large longitudinal resistance.