Ultrafast Structure Switching through Nonlinear Phononics

TL;DR

This paper demonstrates ultrafast control of lattice structure in ErFeO3 via nonlinear phononics, showing how optical pulses can induce transient distortions through phonon coupling, enabling potential lattice switching applications.

Contribution

It introduces a theoretical framework combining density functional theory and anharmonic phonon modeling to predict ultrafast lattice control via nonlinear phononics.

Findings

Transient lattice distortion driven by nonlinear phonon coupling.

Distortion direction controlled by light polarization.

Universal mechanism applicable to perovskite structures.

Abstract

We describe an ultrafast coherent control of the transient structural distortion arising from nonlinear phononics in ErFeO$_3$. Using density functional theory, we calculate the structural properties as input to an anharmonic phonon model that describes the response of the system to a pulsed optical excitation. We find that the trilinear coupling of two orthogonal infrared-active phonons to a Raman-active phonon causes a transient distortion of the lattice. The direction of the distortion is determined by the polarization of the exciting light, suggesting a route to nonlinear phononic lattice control and switching. Since the occurrence of the coupling is determined by the symmetry of the system we propose that it is a universal feature of orthorhombic and tetragonal perovskites.