AB-INITIO SIMULATIONS OF SILVER FILM ADHESION ON ALPHA-AL2O3(0001) AND MGO(100) SURFACES

The atomic and electronic structure of the Ag/MgO (1 0 0) and Ag/alpha -Al2O3(0 0 0 1) interfaces are calculated by means of the ab initio Ha rtree-Fock approach combined with a supercell model. The electronic de nsity distribution and the interface binding energy/equilibrium distan ce for both interfaces are analyzed. For a complete (1:1) surface cove rage of the MgO surface the energetically most favorable adsorption po sition for the Ag atom is above the O atom. For the Ag/alpha-Al2O3 int erface the preferable adsorption positions for the Ag atom are over ce nters of either large equilateral oxygen triangles (in Al-substituted sites of Al-terminated corundum surface) or isosceles oxygen triangles (over O atoms of a first internal oxygen layer) in O-terminated corun dum. This interface is less stable than Ag/MgO (1 O 0), due to a large mismatch between lattice constants of Ag (1 1 1) and alpha-Al2O3 (O O O 1) surfaces as well as the instability of Ag atoms on the Al-termin ated corundum surface. (C) 1998 Elsevier Science B.V. All rights reser ved.