title: Fate of half-metallicity near interfaces: the case of NiMnSb/MgO and NiMnSi/MgO.
abstract: The electronic and magnetic properties of the interfaces between the half-metallic Heusler alloys NiMnSb, NiMnSi, and MgO have been investigated using first-principles density-functional calculations with projector augmented wave potentials generated in the generalized gradient approximation. In the case of the NiMnSb/MgO (100) interface, the half-metallicity is lost, whereas the MnSb/MgO contact in the NiMnSb/MgO (100) interface maintains a substantial degree of spin polarization at the Fermi level (∼60%). Remarkably, the NiMnSi/MgO (111) interface shows 100% spin polarization at the Fermi level, despite considerable distortions at the interface, as well as rather short Si/O bonds after full structural optimization. This behavior markedly distinguishes NiMnSi/MgO (111) from the corresponding NiMnSb/CdS and NiMnSb/InP interfaces.
authors.affiliation: Institute of Physics, University of Augsburg , 86135 Augsburg, Germany.
authors.forename: Rui-Jing
authors.initials: RJ
authors.lastname: Zhang
authors.forename: Ulrich
authors.initials: U
authors.lastname: Eckern
authors.forename: Udo
authors.initials: U
authors.lastname: Schwingenschlögl