Ab initio study of electronic densities of states at copper-alumina interfaces

The electronic structure of Cu(1 1 1)/alpha-Al2O3(0 0 0 1) interfaces with two experimentally observed orientation relationships were studied in terms of local site and angular-momentum-projected electronic densities of states. The electronic band structures were calculated using density functional theory in the local density approximation. The local densities of unoccupied states are compared with experimentally determined electron energy loss near-edge structures. A very good coincidence was found for the interfacial oxygen and aluminum atoms. Interpretation guidelines for the electron energy-loss near-edge structures (ELNES) are suggested for further experimental measurements. The local bonding across the interface is analyzed in terms of local densities of occupied states.