Numerical study of the topological Anderson insulator in HgTe/CdTe quantum wells

TL;DR

This study investigates how disorder induces a transition to a topological Anderson insulator in HgTe/CdTe quantum wells, revealing quantized conductance and edge states through numerical simulations.

Contribution

It provides a detailed numerical analysis of disorder effects leading to the topological Anderson insulator phase in HgTe/CdTe quantum wells, highlighting the role of edge states and local currents.

Findings

Disorder induces quantized conductance in HgTe/CdTe quantum wells.

Topological edge states cause anomalous quantized plateaus.

Local current distributions explain disorder-induced phenomena.

Abstract

We study the disorder effect on the transport properties in the HgTe/CdTe semiconductor quantum wells. We confirm that at a moderate disorder strength, the initially un-quantized two terminal conductance becomes quantized, and the system makes a transition to the novel topological Anderson insulator (TAI). Conductances calculated for the stripe and cylinder samples reveal the topological feature of TAI and supports the idea that the helical edge states may cause the anomalous quantized plateaus. The influence of disorder is studied by calculating the distributions of local currents. Base on the above-mentioned picture, the phenomena induced by disorder in the quantum spin Hall region and TAI region are directly explained. Our study of the local current configurations shed further light on the mechanism of the anomalous plateau.