Decoupling edge versus bulk conductance in the trivial regime of an InAs/GaSb double quantum well using Corbino ring geometry

TL;DR

This study uses a Corbino ring geometry to distinguish edge and bulk conductance in InAs/GaSb quantum wells, revealing temperature-insensitive edge conductance in the trivial regime and identifying it as n-type.

Contribution

It introduces a resistor network model to quantitatively separate edge and bulk conductance, demonstrating the presence of trivial edge conductance in a topological system.

Findings

Edge conductance exists in the trivial regime.

Edge conductance shows temperature-insensitive linear resistivity (~2 kOhm/um).

Trivial edge conductance is identified as n-type.

Abstract

A Corbino ring geometry is utilized to analyze edge and bulk conductance of InAs/GaSb quantum well structures. We show that edge conductance exists in the trivial regime of this theoretically-predicted topological system with a temperature insensitive linear resistivity per unit length in the range of 2 kOhm/um. A resistor network model of the device is developed to decouple the edge conductance from the bulk conductance, providing a quantitative technique to further investigate the nature of this trivial edge conductance, conclusively identified here as being of n-type.