Charge ordering in oxides : a conundrum solved by resonant diffraction

TL;DR

This paper demonstrates that charge ordering in mixed-valence 3d transition metal oxides during structural transitions can be effectively characterized using resonant x-ray scattering combined with ab initio calculations, resolving longstanding ambiguities.

Contribution

It introduces a combined experimental and computational approach to accurately determine charge order and atomic charges in oxides, clarifying the nature of electron reorganization.

Findings

Charge ordering involves only a small fraction of electrons.

Resonant x-ray scattering effectively reveals charge arrangements.

Ab initio calculations support experimental charge evaluations.

Abstract

We show that in mixed-valence 3d transition metal oxides undergoing a structural transition, the low temperature phase results from an effective ordering of the charge. This arrangement and the quantitative evaluation of the atomic charges are determined by using resonant x-ray scattering experiments further analyzed with the help of ab initio calculations of the corresponding scattering factors. We have found that this reorganization concerns only a small fraction of electron and is necessary to reconcile all the experimental data.