Quantifying the stability of the anion ordering in SrVO$_2$H

TL;DR

This study uses first-principles calculations to understand the factors stabilizing the anion ordering in SrVO$_2$H, revealing the roles of crystal field effects and hydrogen positioning in transition metal oxyhydrides.

Contribution

It provides a theoretical explanation for the stabilization of anion ordering in SrVO$_2$H, highlighting the influence of crystal field preferences and hydrogen arrangement.

Findings

Trans preference driven by crystal field stabilizes the observed anion order.

Coherent V-H-V directional shrinkage contributes to stability.

Insights aid in controlling anion ordering in transition metal oxyhydrides.

Abstract

We investigate a text-book mixed-anion compound SrVO$_2$H using first-principles calculation, to theoretically pin down the factors that stabilize its anion ordering. We find that the $trans$ preference by the characteristic crystal field in the VO$_4$H$_2$ octahedron in addition to a coherent shrinkage along the V-H-V direction, taking place when such direction is consistent among neighboring hydrogens, stabilize the anion ordering observed in experiment. Our study gives an important clue for controlling the anion ordering in transition metal oxyhydrides.