The potentials of a copper atom as functions of position outside the MgO surface were evaluated ab initio. These all-electron calculations were carried out with a sufficiently complete localized basis set within the local-density approximation. The MgO(001) surface was simulated by the corresponding surface of finite clusters of various sizes; this procedure was found to give a reasonable approximation to the infinite surface. Potentials were evaluated as functions of distance for the configurations with the copper atom above a surface oxygen atom, a surface magnesium atom, and the hollow site halfway between two oxygen atoms. The deepest potential well was found to be the one for the copper atom above the surface oxgyen atom. The mechanism for the bonding between the copper atom and the surface was found to be the interaction between the copper 4s state and the oxygen 2p band.

• Received 30 January 1995

DOI:https://doi.org/10.1103/PhysRevB.52.6067