Terahertz Driven Reversible Topological Phase Transition of Monolayer Transition Metal Dichalcogenides.

Jian Zhou,Yongliang Shi,Haowei Xu,Ju Li

doi:10.1002/advs.202003832

Abstract

This paper shows how terahertz light can drive ultrafast topological phase transitions in monolayer transition metal dichalcogenides (TMDs). The phase transition is induced by the light interaction with both electron and phonon subsystems in the material. The mechanism of such a phase transition is formulated by thermodynamics theory: the Gibbs free energy landscape can be effectively modulated under light, and the relative stability between different (meta‐)stable phases can be switched. This mechanism is applied to TMDs and reversible phase transitions between the topologically trivial 2H and nontrivial 1T′ phases are predicted, providing appropriate light frequency, polarization, and intensity are applied. The large energy barrier on the martensitic transformation path can be significantly reduced, yielding a small energy barrier phase transition with fast kinetics. Compared with other phase transition schemes, light illumination has great advantages, such as its non‐contact nature and easy tunability. The reversible topological phase transition can be applicable in high‐resolution fast data storage and in‐memory computing devices.

Highlights

The MIT Faculty has made this article openly available
The transition saddle point (SP) structure of MoTe2 is obtained through cell-variable nudged-elastic band calculation
Our theory on THz driven topological phase transition provides another route for optomechanical manipulations of the materials phase, by incorporating both photon–electron and photon–phonon coupling

Summary

Introduction

The MIT Faculty has made this article openly available. Please share how this access benefits you. The phase transition is induced by the light interaction with both electron and phonon subsystems in the material. The mechanism of such a phase transition is formulated by thermodynamics theory: the Gibbs free energy landscape can. Different phases of materials can be classified by their electronic band topological indices, be effectively modulated under light, and the relative stability between which serve as indicators of various exotic different (meta-)stable phases can be switched. This mechanism is applied to properties.[1] For example, the topologically. Topological phase transitions between these phases have evoked tremendous attention, owing to their scientific and technological importance.[2]

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