First-Principles Calculations of Metal/Oxide Interfaces: Effects of Interface Stoichiometry
Ab initio pseudopotential calculations of Cu/Al2O3 and Au/TiO2 interfaces have revealed strong effects of interface stoichiometry. About the Cu/Al2O3 system used for coatings and electronic devices, the interfacial bond of the O-terminated (O-rich) Cu/Al2O3(0001) interface is very strong with ionic and covalent Cu-O interactions, although that of the Al-terminated (stoichiometric) one is rather weak with electrostatic and Cu-Al hybridization interactions. About the Au/TiO2 system with unique catalytic activity, the adhesive energy between non-stoichiometric (Ti-rich or O-rich) TiO2(110) surface and a Au layer is very large, and there occur substantial charge transfer and orbital hybridization, which should have close relations to the catalytic activity.
Masaaki Naka and Toshimi Yamane
M. Kohyama et al., "First-Principles Calculations of Metal/Oxide Interfaces: Effects of Interface Stoichiometry ", Materials Science Forum, Vol. 502, pp. 27-32, 2005