Strain tuning of topological band order in cubic semiconductors

TL;DR

This paper investigates how applying external strain to cubic semiconductors can induce topological phase transitions, transforming trivial insulators into topological insulators through band inversion.

Contribution

It provides a theoretical framework and DFT validation showing strain-induced topological phase transitions in cubic semiconductors, especially InSb.

Findings

Lattice expansion can induce topological phase transition in cubic semiconductors.

A 2-3% biaxial lattice expansion converts InSb into a topological insulator.

Breaking cubic symmetry leads to a topological insulating phase.

Abstract

We theoretically explore the possibility of tuning the topological order of cubic diamond/zinc-blende semiconductors with external strain. Based on the tight-binding model, we analyze the evolution of the cubic semiconductor band structure under hydrostatic or biaxial lattice expansion, by which a generic guiding principle is established that lattice \emph{expansion} can induce a topological phase transition of small band-gap cubic semiconductors via a band inversion, and further breaking of the cubic symmetry leads to a topological insulating phase. Using density functional theory calculations, we demonstrate that a prototype topological trivial semiconductor, InSb, is converted to a nontrivial topological semiconductor with a 2%-3% biaxial lattice expansion.