Electron-Elastic-Wave Interaction in a Two-Dimensional Topological Insulator

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 the 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 crystal 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.