A new topological insulator - \beta-InTe strained in the layer plane

TL;DR

This study explores how biaxial strain in eta-InTe layered crystals induces a topological phase transition, revealing a Dirac cone surface state characteristic of topological insulators through detailed band structure calculations.

Contribution

It demonstrates that biaxial strain can induce a topological insulator phase in eta-InTe, with a band inversion and Dirac cone surface states, expanding the understanding of strain-induced topological phases.

Findings

Band gap collapses at 6% strain

Band inversion occurs with further strain

Surface states form a Dirac cone after including spin-orbit coupling

Abstract

We have investigated the band structure of the bulk crystal and the (001) surface of the \beta-InTe layered crystal subjected to biaxial stretching in the layer plane. The calculation has been carried out using the full-potential linearized augmented plane wave method (FP LAPW) implemented in WIEN2k. It has been shown that at the strain \Deltaa/a=0.06, where a is the lattice parameter in the layer plane, the band gap in the electronic spectrum collapses. With further strain increase a band inversion occurs. The inclusion of the spin-orbit interaction reopens the gap in the electronic spectrum of a bulk crystal, and our calculations show that the spectrum of the surface states has the form of a Dirac cone, typical for topological insulators.