Strongly momentum-dependent screening dynamics in La$_{0.5}$Sr$_{1.5}$MnO$_4$ observed with resonant inelastic x-ray scattering

TL;DR

This study reveals highly localized, momentum-dependent charge screening dynamics in La$_{0.5}$Sr$_{1.5}$MnO$_4$, observed via resonant inelastic x-ray scattering, indicating exciton-like screening clouds of about half an interatomic distance.

Contribution

It demonstrates the momentum-dependent local charge screening in La$_{0.5}$Sr$_{1.5}$MnO$_4$ and links it to highly localized, exciton-like screening clouds, supported by experimental and theoretical analysis.

Findings

Screening dynamics are strongly momentum-dependent.

Screening cloud size is about 0.4-0.5 interatomic distances.

Screening is highly localized, not delocalized.

Abstract

We report strongly momentum-dependent local charge screening dynamics in CE-type charge, orbital, and spin ordered La$_{0.5}$Sr$_{1.5}$MnO$_4$, based on Mn K-edge resonant inelastic x-ray scattering data. Through a comparison with theoretical calculations, we show that the observed momentum dependence reflects highly localized, nearest neighbor screening of the transient local charge perturbation in this compound with an exciton-like screening cloud, rather than delocalized screening. The size of the screening cloud is estmated to be about 0.4-0.5 interatomic distances.