High charge carrier density at the NaTaO_3/SrTiO-3 hetero-interface

摘要

The formation of a (quasi) two-dimensional electron gas between the band insulators NaTaO_3 and SrTiO_3 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)~-/(TiO_2)° and n-type (TaO_2)~+/(SrO)° 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.