Pressure-induced topological phase transition in polar semiconductor BiTeBr

TL;DR

This study combines experimental measurements and first-principles calculations to demonstrate a pressure-induced topological phase transition in BiTeBr, changing from trivial to non-trivial topological states around 2.9 GPa.

Contribution

It provides the first comprehensive investigation of the pressure-driven topological phase transition in BiTeBr using combined experimental and theoretical approaches.

Findings

Band gap closes at 2.9 GPa and re-opens at higher pressures.

Topological nature changes from trivial to non-trivial at 2.9 GPa.

Resistivity shifts from metallic to semiconducting around 3 GPa.

Abstract

We performed X-ray diffraction and electrical resistivity measurement up to pressures of 5 GPa and the first-principles calculations utilizing experimental structural parameters to investigate the pressure-induced topological phase transition in BiTeBr having a noncentrosymmetric layered structure (space group P3m1). The P3m1 structure remains stable up to pressures of 5 GPa; the ratio of lattice constants, c/a, has a minimum at pressures of 2.5 - 3 GPa. In the same range, the temperature dependence of resistivity changes from metallic to semiconducting at 3 GPa and has a plateau region between 50 and 150 K in the semiconducting state. Meanwhile, the pressure variation of band structure shows that the bulk band-gap energy closes at 2.9 GPa and re-opens at higher pressures. Furthermore, according to the Wilson loop analysis, the topological nature of electronic states in noncentrosymmetric BiTeBr at 0 and 5 GPa are explicitly revealed to be trivial and non-trivial, respectively. These results strongly suggest that pressure-induced topological phase transition in BiTeBr occurs at the pressures of 2.9 GPa.