Terahertz Optics Driven Phase Transition in Two-Dimensional Multiferroics

TL;DR

This paper demonstrates that terahertz lasers can induce ultrafast, damage-free phase transitions in two-dimensional multiferroic materials by selectively coupling with phonon modes, potentially advancing data storage technologies.

Contribution

It introduces a novel noncontact method using terahertz lasers to control phase transitions in 2D multiferroics, supported by first-principles calculations.

Findings

Terahertz laser polarization controls phase stability.

Transitions are barrierless and ultrafast.

Selective coupling with optical phonons enables control.

Abstract

Displacive martensitic phase transition is potentially promising in semiconductor based data storage applications with fast switching speed. In addition to traditional phase transition materials, the recently discovered two-dimensional ferroic materials are receiving lots of attention owing to their fast ferroic switching dynamics, which could tremendously boost data storage density and enhance read/write speed. In this study, we propose that a terahertz laser with an intermediate intensity and selected frequency can trigger ferroic order switching in two-dimensional multiferroics, which is a damage-free noncontacting approach. Through first-principles calculations, we theoretically and computationally investigate optically induced electronic, phononic, and mechanical responses of two experimentally fabricated multiferroic (with both ferroelastic and ferroelectric) materials, \b{eta}-GeSe and {\alpha}-SnTe monolayer. We show that the relative stability of different orientation variants can be effectively manipulated via the polarization direction of the terahertz laser, which is selectively and strongly coupled with the transverse optical phonon modes. The transition from one orientation variant to another can be barrierless, indicating ultrafast transition kinetics and the conventional nucleation-growth phase transition process can be avoidable.