BAND-THEORETICAL APPROACH TO BONDING AT METAL-ALUMINA INTERFACES

The electronic structure of the interface between α-Al2O3 (0001) and Nb layers has been calculated using the empirical tight-binding method and the slab model. It has been shown that a direct chemical bond of both covalent and ionic characters can be established at the interface between the surface O atoms of α-Al2O3 and the Nb atoms, which is consistent with the recent experiment. General trends of the electronic structure and chemical bond at the interfaces between α-Al2O3 (0001) and a series of 4d transition metals have been examined. It has been observed that the occupancy in the portion of the antibonding peaks of the local density of states at the interface increases as the atomic number of the transition metal increases