Ta4SiTe4 : A possible one-dimensional topological insulator

Abstract

Using the first-principles calculations, we present a prediction of the nontrivial topological phase in one-dimensional (1D) ${\mathrm{Ta}}_{4}{\mathrm{SiTe}}_{4}$ with high stability further verified by the molecular dynamics simulation and phonon spectrum. In this material, the band inversion intrinsically occurs between $\mathrm{Ta}\text{\ensuremath{-}}d$ and $\mathrm{Te}\text{\ensuremath{-}}p$ orbitals without the spin-orbit coupling effect. As a novel topological insulator, protected by time-reversal symmetry Tˆ and inversion symmetry Pˆ, we explicitly demonstrate the existence of nontrivial topological invariants and the protected edge states in it with a large bulk band gap of $\ensuremath{\sim}163\phantom{\rule{0.28em}{0ex}}\mathrm{meV}$, which could facilitate the experimental verification at the room temperature. In addition, we find its topological states are robust against the external pressure. Our results uncover a potential 1D topological-insulating ${\mathrm{Ta}}_{4}{\mathrm{SiTe}}_{4}$ and promote it as a concrete material platform for exploring the intriguing physics of low-dimensional topological phases.