Topological insulators are non-trivial quantum states of matter which exhibit a gap in the electronic structure of their bulk form, but a gapless metallic electronic spectrum at the surface. Here, we predict a uniaxial strain induced electronic topological transition (ETT) from a band to topological insulating state in the rhombohedral phase (space group: R3ˉm) of As2Te3 (β-As2Te3) through \textit{first-principles} calculations including spin-orbit coupling within density functional theory. The ETT in β-As2Te3 is shown to occur at the uniaxial strain ϵzz = -0.05 (σzz=1.77 GPa), passing through a Weyl metallic state with a single Dirac cone in its electronic structure at the Γ point. We demonstrate the ETT through band inversion and reversal of parity of the top of the valence and bottom of the conduction bands leading to change in the Z2 topological invariant ν0 from 0 to 1 across the transition. Based on its electronic structure and phonon dispersion, we propose ultra-thin films of As2Te3 to be promising for use in ultra-thin stress sensors, charge pumps and thermoelectrics.
@article{arxiv.1406.7119,
title = {Strain induced $\mathbb{Z}_2$ topological insulating state of $\beta$-As$_2$Te$_3$},
author = {Koushik Pal and Umesh V. Waghmare},
journal= {arXiv preprint arXiv:1406.7119},
year = {2015}
}