Interface-induced Topological Insulator Transition in GaAs/Ge/GaAs Quantum Wells

TL;DR

This paper proposes a theoretical method to induce topological insulating phases in germanium through interface engineering in GaAs/Ge/GaAs quantum wells, enabling potential integration into semiconductor devices.

Contribution

The study introduces a novel approach using electric fields and band folding at interfaces to realize topological insulators in common semiconductors like germanium.

Findings

Germanium can be driven into a topological insulator phase via interface engineering.

Giant electric fields at interfaces induce large spin-orbit interactions.

The method offers a new pathway for integrating topological insulators into semiconductor technology.

Abstract

We demonstrate theoretically that interface engineering can drive Germanium, one of the most commonly-used semiconductors, into topological insulating phase. Utilizing giant electric fields generated by charge accumulation at GaAs/Ge/GaAs opposite semiconductor interfaces and band folding, the new design can reduce the sizable gap in Ge and induce large spin-orbit interaction, which lead to a topological insulator transition. Our work provides a new method on realizing TI in commonly-used semiconductors and suggests a promising approach to integrate it in well developed semiconductor electronic devices.