Electron-elastic-wave interaction in a two-dimensional topological insulator

TL;DR

This paper extends the 2D topological insulator model to include electron-elastic wave interactions, revealing how elastic waves can tune transport properties and affect edge state backscattering in materials like HgTe and InAs-GaSb.

Contribution

The study introduces a new extended model of 2D topological insulators that incorporates electron-elastic wave coupling, enabling more realistic analysis of edge state backscattering and transport control.

Findings

Elastic waves can be used to tune charge carrier transport in 2DTIs.

The interaction affects edge state backscattering mechanisms.

Different carrier types interact with elastic waves differently due to symmetry.

Abstract

The interaction between an electron and an elastic wave is investigated for HgTe and InAs-GaSb quantum wells. The well-known Bernevig-Hughes-Zhang model, i.e., the $4\times 4$ model for a two-dimensional (2D) topological insulator (TI), is extended to include terms that describe the coupling between the electron and the elastic wave. The influence of this interaction on the transport properties of the 2DTI and of the edge states is discussed. As the electron-like and hole-like carriers interact with the elastic wave differently due to the cubic symmetry of the 2DTI, one may utilize the elastic wave to tune/control the transport property of charge carriers in the 2DTI. The extended 2DTI model also provides the possibility to investigate the backscattering of edge states of a 2DTI more realistically.