Spin-filtering multiferroic-semiconductor heterojunctions

We report on the structural and electronic properties of the interface between the multiferroic oxide YMnO3 and semiconductor GaN studied with the Hubbard-corrected local-spin-density approximation to density-functional theory. We find that the band offsets at the interface between antiferromagnetically ordered YMnO3 and GaN are different for spin-up and spin-down states. This behavior is due to the spin splitting of the valence band induced by the interface. The energy barrier depends on the relative orientation of the electric polarization with respect to the polarization direction of the GaN substrate suggesting an opportunity to create magnetic tunnel junctions in this material system. (c) 2007 American Institute of Physics.