Strain-induced topological phase transition in two-dimensional platinum ditelluride

TL;DR

This study uses density functional theory to show that biaxial tensile strain can induce a topological phase transition in 2D platinum ditelluride, transforming it from a trivial insulator to a topological insulator at 19.3% strain.

Contribution

It reveals the strain-induced topological phase transition in 2D $PtTe_2$, highlighting a unique gap closing at M points and potential for electronic applications.

Findings

$PtTe_2$ is initially a trivial insulator with a 0.347 eV gap.

Biaxial tensile strain of 19.3% induces a transition to a topological insulator.

The phase transition involves band inversion and gap closing at M points.

Abstract

Topological phase transition is a hot topic in condensed matter physics and computational material science. Here, we investigate the electronic structure and phonon dispersion of the two-dimensional (2D) platinum ditelluride ($PtTe_2$) using the density functional theory. It is found that the $PtTe_2$ monolayer is a trivial insulator with an indirect band gap of 0.347eV. Based on parity analysis, the biaxial tensile strain can drive the topological phase transition. As the strain reaches 19.3%, $PtTe_2$ undergoes a topological phase transition, which changes from a trivial band insulator to a topological insulator with $Z_2=1$. Unlike conventional honeycomb 2D materials with topological phase transition, which gap closes at K points, the strained $PtTe_2$ monolayer becomes gapless at M points under critical biaxial strain. The band inversion leads the switch of the parities near the Fermi level, which gives rise to the topological phase transition. The novel monolayer $PtTe_2$ has a potential application in the field of micro-electronics.