Optical conductivity of the type-II Weyl semimetal WTe$_2$ under pressure

TL;DR

This study investigates how external pressure affects the optical conductivity of WTe$_2$, revealing significant spectral changes and phase transition signatures, thus highlighting the material's high electronic sensitivity to pressure.

Contribution

It provides the first detailed analysis of pressure-dependent optical conductivity in WTe$_2$, linking spectral features to electronic and structural phase transitions.

Findings

Spectral weight transfer from high to low energy with pressure

Anomalies at approximately 2 GPa and 4.5 GPa indicating phase transitions

High sensitivity of electronic band structure to external pressure

Abstract

Tungsten ditelluride WTe$_2$ is a type-II Weyl semimetal with electronic properties highly sensitive to external pressure, as demonstrated by the superconductivity emerging under pressure. Here, we study the optical conductivity of the type-II Weyl semimetal WTe$_2$ under external pressure at room temperature. With increasing pressure, a pronounced spectral weight transfer occurs from the high-energy to the low-energy interband transitions, with drastic changes in the profile of the optical conductivity spectrum indicating a high sensitivity of the electronic band structure to external pressure. The detailed analysis of the pressure-dependent optical conductivity furthermore reveals anomalies at the pressures $\sim$2 and $\sim$4.5~GPa, where an electronic and a structural phase transition, respectively, were reported in the literature.