Nonlinear electron-phonon coupling in doped manganites

TL;DR

This study uses time-resolved resonant x-ray diffraction to explore how nonlinear electron-phonon interactions influence charge order melting and phase transitions in doped manganites, revealing anharmonic coupling effects.

Contribution

It demonstrates direct anharmonic coupling between lattice vibrations and electronic structure, offering new insights into nonlinear phonon control of material properties.

Findings

Charge order reduces nonlinearly with excitation fluence

Anharmonic coupling drives charge order melting

Potential for nonlinear phonon control in materials

Abstract

We employ time-resolved resonant x-ray diffraction to study the melting of charge order and the associated insulator-metal transition in the doped manganite Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ after resonant excitation of a high-frequency infrared-active lattice mode. We find that the charge order reduces promptly and highly nonlinearly as function of excitation fluence. Density functional theory calculations suggest that direct anharmonic coupling between the excited lattice mode and the electronic structure drive these dynamics, highlighting a new avenue of nonlinear phonon control.