Metal-insulator transition and local-moment collapse in FeO under pressure

TL;DR

This study uses advanced computational methods to investigate how FeO's electronic structure and lattice properties change under high pressure, revealing a spin transition and metal-insulator transition linked to lattice collapse.

Contribution

It demonstrates a combined ab initio and dynamical mean-field theory approach to uncover pressure-induced spin and metal-insulator transitions in FeO.

Findings

High-spin to low-spin transition above 73 GPa

Orbital-selective Mott metal-insulator transition

8.5% lattice volume collapse at transition

Abstract

We employ a combination of the \emph{ab initio} band structure methods and dynamical mean-field theory to determine the electronic structure and phase stability of paramagnetic FeO at high pressure and temperature. Our results reveal a high-spin to low-spin transition within the B1 crystal structure of FeO upon compression of the lattice volume above 73~GPa. The spin-state transition is accompanied by an orbital-selective Mott metal-insulator transition (MIT). The lattice volume is found to collapse by about 8.5~\% at the MIT, implying a complex interplay between electronic and lattice degrees of freedom. Our results for the electronic structure and lattice properties are in overall good agreement with experimental data.