Confinement Effect Driven Quantum Spin Hall Effect in Monolayer AuTe2Cl

TL;DR

This paper predicts that monolayer AuTe2Cl is a quantum spin Hall insulator with a 10 meV band gap, driven by confinement effects causing band inversion, and suggests it can be experimentally realized by exfoliation.

Contribution

The study reveals the topological nature of monolayer AuTe2Cl driven by confinement effects, supported by first-principles calculations, and proposes its experimental realization from bulk material.

Findings

Monolayer AuTe2Cl is a QSH insulator with a 10 meV band gap.

Band inversion caused by confinement effects underpins the topological phase.

Bulk AuTe2Cl can be exfoliated to obtain the monolayer for experimental observation.

Abstract

Based on first-principles calculations, we predict that the monolayer AuTe2Cl is a quantum spin Hall (QSH) insulator with a topological band gap about 10 meV. The three-dimensional (3D) AuTe2Cl is a topological semimetal that can be viewed as the monolayer stacking along b axis. By studying the energy level distribution of p orbitals of Te atoms for the bulk and the monolayer, we find that the confinement effect driven p_y^- and p_z^+ band inversion is responsible for the topological nontrivial nature of monolayer. Since 3D bulk AuTe2Cl has already been experimentally synthesized, we expect that monolayer AuTe2Cl can be exfoliated from a bulk sample and the predicted QSH effect can be observed.