Abstract
The high-pressure electronic structures and the phase stability of MnO and FeO were studied with the first-principles plane-wave basis pseudopotential calculations based on generalized gradient approximation (GGA) supplemented by the LDA+U method. The present calculations account well for the properties of MnO and FeO especially in the high-pressure region. Our results predict that the high-pressure phase of MnO should take the normal NiAs (nB8) structure rather than the CsCl (B2) structure. A very unique antiferromagnetic (AF) inverse B8 (iB8) structure rather than the nB8 structure is predicted as the high-pressure phase of FeO. Moreover, this AF iB8 structure with the stoichiometric composition should be a band insulator even under high-pressure.