Orbital-Selective Pressure-Driven Metal to Insulator Transition in FeO from Dynamical Mean-Field Theory

Abstract

In this work we report the LDA+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 Fe3d 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 Fe2 O3 (d5 configuration) where metal-insulator transition is accompanied by high-spin to low-spin transition, in FeO (d6 configuration) average value of magnetic moment √ μz2 is nearly the same in the insulating phase at AP and metallic phase at HP in agreement with x-ray spectroscopy data. The metal-insulator transition is orbital selective with only t2g orbitals demonstrating spectral function typical for strongly correlated metal (well pronounced Hubbard bands and narrow quasiparticle peak) while e g states remain insulating. © 2010 The American Physical Society.