Determining the Electron-Phonon Coupling Strength in Correlated Electron Systems from Resonant Inelastic X-ray Scattering

TL;DR

This paper demonstrates that high-resolution RIXS can directly measure the electron-phonon coupling strength in correlated electron systems by analyzing phonon scattering and loss ratios, enabling absolute energy scale quantification.

Contribution

It introduces a method to extract electron-phonon coupling strength from RIXS spectra using differential cross sections and phonon loss ratios, providing a direct and element-specific measurement.

Findings

RIXS spectra can reveal electron-phonon coupling strength.

The differential phonon scattering cross section is key to extraction.

The phonon loss ratio relates directly to coupling strength and core-hole lifetime.

Abstract

We show that high resolution Resonant Inelastic X-ray Scattering (RIXS) provides direct, element-specific and momentum-resolved information on the electron-phonon (e-p) coupling strength. Our theoretical analysis demonstrates that the e-p coupling can be extracted from RIXS spectra by determining the differential phonon scattering cross section. An alternative, very direct manner to extract the coupling is to use the one and two-phonon loss ratio, which is governed by the e-p coupling strength and the core-hole life-time. This allows measurement of the e-p coupling on an absolute energy scale.