Tunable Quantum Spin Hall Effect via Strain in two-Dimensional Arsenene Monolayer

TL;DR

This study demonstrates how applying strain to arsenene monolayer induces a topological phase transition, enabling tunable quantum spin Hall states with potential for nanoelectronic applications.

Contribution

First-principles calculations reveal strain-driven topological phase transition in arsenene, establishing a tunable QSH effect and proposing BN as a suitable substrate.

Findings

Band gap decreases with strain and becomes direct

Band inversion occurs at 11.14% strain leading to topological state

A single pair of helical edge states confirms QSH effect

Abstract

The search for new quantum spin Hall (QSH) phase and effective manipulations of their edge states are very important for both fundamental sciences and practical applications. Here, we use first-principles calculations to study the strain-driven topological phase transition of two-dimensional (2D) arsenene monolayer. We find that the band gap of arsenene decreases with increasing strain and changes from indirect to direct, and then the s-p band inversion takes place at {\Gamma} point as the tensile strain is larger than 11.14%, which lead to a nontrivially topological state. A single pair of topologically protected helical edge states is established for the edge of arsenene, and their QSH states are confirmed with nontrivial topological invariant Z2 = 1. We also propose high-dielectric BN as an ideal substrate for the experimental synthesis of arsenene, maintaining its nontrivial topology. These findings provide a promising candidate platform for topological phenomena and new quantum devices operating at nanoelectronics.