d0 Ferromagnetic Interface between Nonmagnetic Perovskites.

We use computational and experimental methods to study d° ferromagnetism at a charge-imbalanced interface between two perovskites. In SrTi03/KTa03 superlattice calculations, the charge imbalance introduces holes in the SrTiO3 layer, inducing a d0 ferromagnetic half-metallic 2D hole gas at the interface oxygen 2p orbitals. The charge imbalance overrides doping by vacancies at realistic concentrations. Varying the constituent materials shows ferromagnetism to be a general property of hole-type d0 perovskite interfaces. Atomically sharp epitaxial d0 SrTi03/KTa03, SrTi03/KNb03, and SrTi03/NaNb03 interfaces are found to exhibit ferromagnetic hysteresis at room temperature. We suggest that the behavior is due to the high density of states and exchange coupling at the oxygen tig band in comparison with the more studied d band t2g symmetry electron gas. [ABSTRACT FROM AUTHOR]