The metallic interface between the two band insulators LaGaO₃ and SrTiO₃

The formation of metallic interface states between the two band insulators LaGaO₃ and SrTiO₃ is studied by the full-potential linearized augmented plane-wave method based on density functional theory. Structural optimization of the atomic positions points to only small changes of the chemical bonding at the interface. The n-type (LaO/TiO₂) and p-type (GaO₂/SrO) interfaces turn out to be metallic. Reduction of the O content increases the conductivity of the n-type interface, while the p-type interface can be turned gradually from a hole doped into an electron doped state.