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 Hartree-Fock approach combined with a supercell model. The

electronic density distribution and the interface binding

energy/equilibrium distance for both interfaces are analyzed. For a

complete (1:1) surface coverage of the MgO surface the energetically

most favorable adsorption position for the Ag atom is above the O atom.

For the Ag/alpha-Al2O3 interface the preferable adsorption positions

for the Ag atom are over centers 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 corundum. 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-terminated corundum surface. (C) 1998 Elsevier

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