Relative importance of crystal field versus bandwidth to the high pressure spin transition in transition metal monoxides

TL;DR

This study uses density functional theory to compare how crystal field splitting and bandwidth evolve under pressure in transition metal monoxides, highlighting the dominant role of bandwidth in spin transitions.

Contribution

It provides a detailed analysis showing that bandwidth increases more than crystal field splitting under pressure, emphasizing bandwidth's importance in spin collapse phenomena.

Findings

Bandwidth exceeds crystal field splitting over pressure range

Bandwidth increases more rapidly than crystal field splitting with pressure

Bandwidth plays a crucial role in pressure-induced spin transitions

Abstract

The crystal field splitting and d bandwidth of the 3d transition metal monoxides MnO, FeO, CoO and NiO are analyzed as a function of pressure within density functional theory. In all four cases the 3d bandwidth is significantly larger than the crystal field splitting over a wide range of compressions. The bandwidth actually increases more as pressure is increased than the crystal field splitting. Therefore the role of increasing bandwidth must be considered in any explanation of a possible spin collapse that these materials may exhibit under pressure.