Orbital ordering, Jahn-Teller distortion, and anomalous X-Ray scattering in Manganates

TL;DR

This paper uses LSDA+U calculations to show that K edge x-ray scattering in manganates is primarily influenced by band structure effects related to bond distortions and orbital occupation, challenging previous local interaction models.

Contribution

It introduces a new mechanism for K edge x-ray scattering in manganates, emphasizing band structure effects over local Coulomb interactions.

Findings

X-ray scattering sensitive to orbital ordering and Jahn-Teller distortion in specific energy ranges.

Band structure effects dominate polarization dependence of K edge scattering.

Proposes a general mechanism applicable to transition metal compounds.

Abstract

We demonstrate with LSDA+U calculations that x-ray scattering at the K edge of Mn is sensitive to orbital ordering in one energy range and Jahn-Teller distortion in another. Contrary to what is suggested by atomic or cluster models used to date we show that band structure effects rather than local Coulomb interactions dominate the polarization dependence of the K edge scattering and therefore it is sensitive to nearest neighbour bond length distortions and next nearest neighbour orbital occupation. Based on this we propose a new mechanism for K edge x-ray scattering in the manganates which we suggest is also applicable to transition metal compounds in general.