ELECTRONIC-STRUCTURE CALCULATIONS OF TRANSITION-METAL ALUMINA INTERFACES

The electronic structures of the Nb-Al2O3 interfaces have been calculated using the tight-binding electronic theory. It has been shown by using the models of the Al2O3 (0001) slab with Nb layer deposited, that a direct chemical bond of both covalent and ionic characters can be established between the surface O atoms of Al2O3 and the Nb atoms. This result is consistent with recent photoelectron spectroscopy studies. It is possible that the present type of interfacial bond is the origin of adhesion and stabilization of the observed abrupt Nb-Al2O3 interfaces. General trends of the electronic structure and chemical bond at the interfaces between Al2O3 and a series of 4d transition metals have also been examined using the same theoretical method. We have presented a systematic perspective of the bonding nature and reactivity at the transition metal-Al2O3 interfares from a viewpoint of both the metal-surface O interaction and the metal-surface Al interaction.