Strain induced topological phase transitions in monolayer honeycomb structures of group-V binary compounds

TL;DR

This study uses first-principles calculations to explore how strain induces topological phase transitions in 2D honeycomb structures of group-V binary compounds, revealing tunable electronic properties and phase changes.

Contribution

It demonstrates that lattice strain can induce topological phase transitions in 2D group-V binary compounds, independent of spin-orbit coupling effects.

Findings

Materials are stable semiconductors with tunable band gaps.

Strain causes transitions from semiconductor to topological insulator.

Topological phase transition occurs via band inversion at the Γ point.

Abstract

We present first-principles calculations of electronic structures of a class of two-dimensional (2D) honeycomb structures of group-V binary compounds. Our results show these new 2D materials are stable semiconductors with direct or indirect band gaps. The band gap can be tuned by applying lattice strain. During their stretchable regime, they all exhibit metal-indirect gap semiconductor-direct gap semiconductor-topological insulator (TI) transitions with increasing strain from negative (compressive) to positive (tensile) values. The topological phase transition results from the band inversion at $\Gamma$ point due to lattice strain and is irrelevant to spin-orbit coupling (SOC).