Asymmetric quantum Hall effect and diminished $\nu=0$ longitudinal resistance in graphene/InSe heterostructures

TL;DR

This paper studies quantum transport in graphene/InSe heterostructures, revealing asymmetries and zero longitudinal resistance at high magnetic fields, explained by density gradients and edge currents, with implications for quantum Hall device engineering.

Contribution

It introduces a model combining density gradients and edge current effects to explain asymmetric quantum Hall transport in heterostructures, advancing understanding of edge phenomena.

Findings

Asymmetries in $R_{xx}$ observed at high magnetic fields.

Vanishing $R_{xx}$ peaks at the charge-neutrality point.

Model explains phenomena via density gradients and edge currents.

Abstract

We investigate quantum transport in graphene/InSe heterostructures and find major asymmetries in the longitudinal resistance ($R_{xx}$) and vanishing $R_{xx}$ peaks at high magnetic fields, particularly at the charge-neutrality point. Our Landauer-Buttiker analysis and numerical simulations show that a monotonically varying density gradient combined with a full equilibration mechanism can explain these phenomena. Our results also suggest the presence of trivial long-range chiral edge current and offer a broadly applicable way to engineer transport properties in quantum Hall systems.