Orbital-selective pressure-driven metal to insulator transition in FeO from dynamical mean-field theory

In this work we report the $\text{LDA}+\text{DMFT}$ (method combining local-density approximation with dynamical mean-field theory) results of magnetic and spectral properties calculation for paramagnetic phases of FeO at ambient and high pressures (HPs). At ambient-pressure (AP) calculation gave FeO as a Mott insulator with $\text{Fe}\text{ }3d$ shell in high-spin state. Calculated spectral functions are in a good agreement with experimental photoemission spectroscopy and IPES data. Experimentally observed metal-insulator transition at high pressure is successfully reproduced in calculations. In contrast to MnO and ${\text{Fe}}_{2}{\text{O}}_{3}$ (${d}^{5}$ configuration) where metal-insulator transition is accompanied by high-spin to low-spin transition, in FeO (${d}^{6}$ configuration) average value of magnetic moment $\sqrt{⟨{\ensuremath{\mu}}_{z}^{2}⟩}$ is nearly the same in the insulating phase at AP and metallic phase at HP in agreement with x-ray spectroscopy data [J. Badro, V. V. Struzhkin, J. Shu, R. J. Hemley, H.-k. Mao, C.-c. Kao, J.-P. Rueff, and G. Shen, Phys. Rev. Lett. 83, 4101 (1999)]. The metal-insulator transition is orbital selective with only ${t}_{2g}$ orbitals demonstrating spectral function typical for strongly correlated metal (well pronounced Hubbard bands and narrow quasiparticle peak) while ${e}_{g}$ states remain insulating.