The effect of in-plane magnetic field and applied strain in quantum spin Hall systems: application to InAs/GaSb quantum wells

TL;DR

This paper investigates how in-plane magnetic fields and strain influence the quantized charge conductance in InAs/GaSb quantum wells, finding robustness against high magnetic fields and potential enhancement of conductance quantization by strain.

Contribution

It provides a theoretical analysis of the effects of magnetic field and strain on quantized conductance in quantum spin Hall systems, with predictions applicable to experimental conditions.

Findings

Conductance quantization remains robust up to 20 Tesla magnetic field.

Strain modeled by disordered hopping can enhance conductance quantization.

Relevance to experimental observations of quantum spin Hall effects in InAs/GaSb.

Abstract

Motivated by the recent discovery of quantized spin Hall effect in InAs/GaSb quantum wells\cite{du2013}$^,$\cite{xu2014}, we theoretically study the effects of in-plane magnetic field and strain effect to the quantization of charge conductance by using Landauer-Butikker formalism. Our theory predicts a robustness of the conductance quantization against the magnetic field up to a very high field of 20 tesla. We use a disordered hopping term to model the strain and show that the strain may help the quantization of the conductance. Relevance to the experiments will be discussed.