Spin-Polarized Energy-Band Structure of Antiferromagnetic MnO

Abstract

A study has been made of the energy‐band structure of antiferromagnetic MnO using a spin‐polarized Augmented Plane Wave procedure. An earlier calculation, which was made using the form of the free‐electron exchange potential originally proposed by J. C. Slater, predicted an energy gap of 2.7 eV. However, it also predicted the valence band to be composed of states having predominantly O²⁻ 2p character. The results of the present calculation, which has been made using a modified form of the free‐electron exchange potential, also leads to the prediction that MnO should be an insulator; however, in this case the valence band is predominantly composed of Mn²⁺ 3d states. These results are in better agreement with the observed optical properties of this compound. In both cases the conduction band is a mixture of Mn²⁺ d and s states. The energy gap separating the two Mn²⁺ d‐bands can be shown to be in large part due to the intra‐atomic exchange splitting of the d‐level of the Mn²⁺ ion.