Voltage control of the quantum scattering time in InAs/GaSb/InAs trilayer quantum wells

TL;DR

This study investigates how gate voltage training influences quantum scattering time in InAs/GaSb/InAs trilayer quantum wells, revealing a method to enhance quantum coherence and potentially improve topological insulator device performance.

Contribution

It demonstrates that gate voltage training can significantly improve quantum scattering time in InAs/GaSb/InAs quantum wells, providing insights into controlling scattering mechanisms in topological insulators.

Findings

Quantum scattering time can be increased by 50% through gate voltage training.

The ratio of quantum to transport scattering time scales linearly with charge carrier density.

Coulombic scattering dominates the scattering mechanisms in the studied heterostructures.

Abstract

We study the evolution of the quantum scattering time by gate voltage training in the topological insulator based on InAs/GaSb/InAs trilayer quantum wells. Depending on the minimal gate voltage applied during a gate voltage sweep cycle, the quantum scattering time can be improved by 50 % from 0.08 ps to 0.12 ps albeit the transport scattering time is rather constant around 1.0 ps. The ratio of the quantum scattering time versus transport scattering time scales linearly with the charge carrier density and varies from 10 to 30, indicating Coulombic scattering as the dominant scattering mechanism. Our findings may enable to improve the residual bulk conductivity issue and help in observing helical edge channels in topological insulators based on InAs/GaSb quantum well heterostructures even for macroscopic devices.