Inelastic x-ray scattering as a probe of electronic correlations

TL;DR

This paper develops an exact dynamical mean field theory to analyze inelastic x-ray scattering in a model that exhibits a quantum critical metal-insulator transition, revealing temperature-dependent charge excitations and their relation to electronic correlations.

Contribution

It introduces an exact DMFT framework for inelastic light scattering in the Falicov-Kimball model, elucidating charge dynamics near a quantum critical point.

Findings

Charge excitations vary with temperature and momentum.

High-energy charge transfer is weakly temperature-dependent.

Results inform on charge dynamics evolution across the transition.

Abstract

We construct an exact dynamical mean field theory for nonresonant inelastic light scattering in the infinite-dimensional Falicov-Kimball model, which can be tuned through a quantum critical metal-insulator transition. Due to the projection of the polarization orientations onto different regions of the Brillouin zone and due to the transfer of energy and momentum from the light to the strongly correlated charge excitations, the nature of the dynamics can be naturally interpreted as strongly temperature-dependent low-energy particle-hole excitations and weakly temperature-dependent high-energy charge transfer excitations which depend delicately on the electronic correlations. These results can be used to give important information concerning the evolution of charge dynamics in different regions of the Brillouin zone.