Critical role of electronic correlations in determining crystal structure of transition metal compounds

TL;DR

This paper demonstrates that strong d-electron correlations significantly influence the crystal structures of transition metal compounds by affecting charge transfer and electrostatic interactions, advancing structure prediction methods for correlated materials.

Contribution

It reveals how orbitally-selective strong correlations impact crystal structure stability and introduces a new perspective for structure prediction in strongly correlated systems.

Findings

Strong d-electron correlations influence energy landscapes.

Charge transfer mechanisms are substantially affected by correlations.

Qualitative behaviors can be explained by simple electrostatics.

Abstract

The choice that a solid system "makes" when adopting a crystal structure (stable or metastable) is ultimately governed by the interactions between electrons forming chemical bonds. By analyzing 6 prototypical binary transition-metal compounds we demonstrate here that the orbitally-selective strong $d$-electron correlations influence dramatically the behavior of the energy as a function of the spatial arrangements of the atoms. Remarkably, we find that the main qualitative features of this complex behavior can be traced back to simple electrostatics, i.e., to the fact that the strong $d$-electron correlations influence substantially the charge transfer mechanism, which, in turn, controls the electrostatic interactions. This result advances our understanding of the influence of strong correlations on the crystal structure, opens a new avenue for extending structure prediction methodologies to strongly correlated materials, and paves the way for predicting and studying metastability and polymorphism in these systems.