Bonding of thin Pd films on (100)SrTiO3 substrates: Ab initio density functional theory investigations

The electronic structure of the Pd/SrTiO3 interface, which serves as a model system for more complex metal/ceramic interfaces, is studies in terms of local site - and momentum-projected densities of states. Band structures were calculated using density functional theory in the local density approximation. By comparing the local densities of unoccupied states to experimentally determined electron energy-loss near-edge structures, a TiO2 termination of the SrTiO3 interface are analyszed by local densities of occupied states overlapping in energy, i.e., by covalent bonding interactions. It is found that the bonding between the Pd and the substrate are dominated by sigma-type bonds across the interface.