High charge carrier density at the NaTaO3/SrTiO3 hetero-interface

The formation of a (quasi) two-dimensional electron gas between the band insulators NaTaO3 and SrTiO3 is studied by means of the full-potential linearized augmented plane-wave method of density functional theory. Optimization of the atomic positions points to only small changes in the chemical bonding at the interface. Both the p-type (NaO)(-)/(TiO2)(0) and n-type (TaO2)(+)/(SrO)(0) interfaces are found to be metallic with high charge carrier densities. The effects of O vacancies are discussed. Spin-polarized calculations point to the formation of isolated O 2p magnetic moments, located in the metallic region of the p-type interface. (C) 2011 American Institute of Physics. [doi:10.1063/1.3625951]