A First-Principles Study of the Ag/a-Al2O3(0001) Interface

Abstract

Ab initio simulations of the Ag/a-Al2O3(0001) interface have been performed for periodic slab models. We have considered Al- and O-terminated corundum surfaces, low and high substrate coverages by silver, as well as the two preferred Ag adsorption sites. The two different terminations give rise to qualitatively different results: silver physisorption on the Al-terminated substrate and chemisorption on O-terminated one. The latter could be treated as a possible model for the defective Al-terminated substrate, where the outermost aluminium ions are removed (completely or partly). This makes O-terminated surface highly reactive towards a deposited metal, in order to restore initial corundum stoichiometry.

Keywords

• metal/oxide interface
• Ag adsorption
• a-Al2O3 (corundum)
• Al- and Oterminated (0001) surfaces
• ab initio
• Hartree-Fock method
• electron correlation corrections