A light-induced Weyl semiconductor-to-metal transition mediated by Peierls instability

TL;DR

This paper demonstrates that impulsive optical excitation can transiently switch elemental tellurium between Weyl semiconductor, Weyl metal, and non-Weyl metal states by controlling Peierls distortion, supported by theoretical and experimental evidence.

Contribution

It introduces a light-induced mechanism to control topological phases in tellurium via Peierls distortion, combining theoretical simulations with experimental validation.

Findings

Optical excitation modulates Peierls distortion amplitude.

Time-resolved measurements confirm inverse-Peierls distortion.

Switching between Weyl and non-Weyl states demonstrated.

Abstract

Elemental tellurium is a strongly spin-orbit coupled Peierls-distorted semiconductor whose band structure features topologically protected Weyl nodes. Using time-dependent density functional theory calculations, we show that impulsive optical excitation can be used to transiently control the amplitude of the Peierls distortion, realizing a mechanism to switch tellurium between three states: Weyl semiconductor, Weyl metal and non-Weyl metal. Further, we present experimental evidence of this inverse-Peierls distortion using time-resolved optical second harmonic generation measurements. These results provide a pathway to multifunctional ultrafast Weyl devices and introduce Peierls systems as viable hosts of light-induced topological transitions.