Laser-driven ferroelectricity in $\mathrm{SrTiO_{3}}$ via quantum fluctuation quenching

TL;DR

This paper demonstrates that resonant mid-infrared pulses can suppress quantum fluctuations in SrTiO3, inducing a metastable ferroelectric state and revealing a new non-equilibrium pathway to control ferroelectricity in oxide perovskites.

Contribution

It introduces a method to control quantum fluctuations with pulsed light, enabling ferroelectric transition in SrTiO3 otherwise prevented by quantum effects.

Findings

Resonant mid-IR pulses induce ferroelectricity in SrTiO3.

Quantum fluctuations can be suppressed in strong out-of-equilibrium regimes.

Predicted long-lived, metastable ferroelectric states under specific conditions.

Abstract

Similar to other perovskites in its family, $\mathrm{SrTiO_{3}}$ exhibits a significant softening of the ferroelectric mode with decreasing temperature, a behavior that typically heralds the onset of a ferroelectric transition. However, this material remains paraelectric down to 0K due to quantum fluctuations that prevent stabilization of the ferroelectric minimum. This work shows that in the strong out-of-equilibrium regime induced by resonant mid-IR pulses, quantum fluctuations can be suppressed, inducing a ferroelectric transition in $\mathrm{SrTiO_{3}}$ that is otherwise impossible at equilibrium. The appearance of a metastable state, that is distinct from the conventional ground state, is the first demonstration of how it is possible to leverage and control quantum fluctuations with pulsed light to qualitatively alter the free energy landscape of a quantum system. We predict the conditions and system parameters under which the induced non-equilibrium state can be long-lived and metastable. In providing a quantitative description, based on first principles machine learned potential energy surface, we explain recent experimental observations of light-induced ferroelectric transition in this material. Our results indicate a general nonequilibrium route to light-induced ferroelectric order in oxide perovskites near a ferroelectric instability.