ELECTRONIC-STRUCTURE AND RELATIVE STABILITY OF THE MGO(001) AND MGO(111) SURFACES

The relative stability and electronic structure of the MgO (001), (111)-Mg, and (111)-O surfaces have been studied with the Harris-Foulkes total energy functional. The computed energies of the (001), (111)-O, and (111)-Mg surfaces of MgO are 2.64, 12.80, and 13.02 J m-2, respectively. Our calculations exhibit a qualitative distinction between the Mg-terminated polar (111) surface, which has a nonzero density of one-electron states at the Fermi level, and the other (001) and (111)-O surfaces which retain the band gap properties of the bulk material. The projected local density of states for atoms in the bulk and at the various surfaces are presented, and used to explain the relative stability of different surfaces in terms of the properties of surface bonds.