Tunable Spatiotemporal Orders in Driven Insulators

TL;DR

This paper demonstrates that intense optical phonon driving can induce tunable, incommensurate spatiotemporal orders in insulators, with potential applications in nanoscale material control using THz waves.

Contribution

It introduces a novel mechanism for creating tunable incommensurate orders in solids through high-fluence phonon driving, with theoretical predictions and experimental proposals.

Findings

Spatiotemporal order oscillates at incommensurate wavevector and half the drive frequency.

Order persists at high temperatures beyond phonon lifetime.

Predictions for time-resolved diffraction in candidate materials.

Abstract

We show that driving optical phonons above a threshold fluence induces spatiotemporal orders, where material properties oscillate at an incommensurate wavevector $q_0$ in space and at half the drive frequency in time. The order is robust against temperature on timescales much larger than the lifetime of the excited modes and can be accompanied by a static $2q_0$ modulation. We make predictions for time-resolved diffraction and provide estimates for candidate materials. Our results show the possibility of using THz waves in solids to realize tunable incommensurate order on the nanoscale.