Ab initio study of the surface and interfacial properties of a layered MgO/NiO film

The equilibrium surface geometries of MgO and NiO, and the surface/interface geometry of layered composite thin films of these two oxides, are computed from first-principles periodic calculations within the unrestricted Hartree-Pock approximation. Calculated binding-energy shifts of the Ni 2p core levels caused by geometric perturbations in the layered films are of the correct order of magnitude to account for published x-ray photoelectron spectroscopy results. Recent spectroscopic data may thus be inter-preted in terms of an ioniclike model with modest surface relaxation