Strain induced $\mathbb{Z}_2$ topological insulating state of $β$-As$_2$Te$_3$

Koushik Pal; Umesh V. Waghmare

doi:10.1063/1.4892941

paper

Strain induced $Z_{2}$ topological insulating state of $β$ -As $_{2}$ Te $_{3}$

arXiv:1406.7119 · doi:10.1063/1.4892941

Abstract

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: R $3 ˉ$ m) of As $_{2}$ Te $_{3}$ ( $β$ -As $_{2}$ Te $_{3}$ ) through \textit{first-principles} calculations including spin-orbit coupling within density functional theory. The ETT in $β$ -As $_{2}$ Te $_{3}$ is shown to occur at the uniaxial strain $ε_{z z}$ = -0.05 ( $σ_{z z}$ =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 $Z_{2}$ topological invariant $ν_{0}$ from 0 to 1 across the transition. Based on its electronic structure and phonon dispersion, we propose ultra-thin films of As $_{2}$ Te $_{3}$ to be promising for use in ultra-thin stress sensors, charge pumps and thermoelectrics.

Strain induced $Z_{2}$ topological insulating state of $β$ -As $_{2}$ Te $_{3}$

Abstract

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Strain induced Z2​ topological insulating state of β-As2​Te3​

Abstract

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Strain induced $Z_{2}$ topological insulating state of $β$ -As $_{2}$ Te $_{3}$