Quantum Hall transport as a probe of capacitance profile at graphene edges

TL;DR

This paper demonstrates how quantum Hall transport can be used as a spatially resolved probe to analyze the capacitance and density profiles at the edges of graphene devices, enhancing understanding of edge channel development.

Contribution

It introduces a practical method to use quantum Hall transport as a probe for inhomogeneous capacitance profiles at graphene edges, linking edge channel formation to local density variations.

Findings

Quantum Hall transport reveals inhomogeneous capacitance near graphene edges.

Edge channels are influenced by local capacitance profiles.

The method provides spatial resolution of density profiles in graphene.

Abstract

The quantum Hall effect is a remarkable manifestation of quantized transport in a two-dimensional electron gas. Given its technological relevance, it is important to understand its development in realistic nanoscale devices. In this work we present how the appearance of different edge channels in a field-effect device is influenced by the inhomogeneous capacitance profile existing near the sample edges, a condition of particular relevance for graphene. We apply this practical idea to experiments on high quality graphene, demonstrating the potential of quantum Hall transport as a spatially resolved probe of density profiles near the edge of this two-dimensional electron gas.