title: Realisation of magnetically and atomically abrupt half-metal/semiconductor interface: Co2FeSi0.5Al0.5/Ge(111).
abstract: Halfmetal-semiconductor interfaces are crucial for hybrid spintronic devices. Atomically sharp interfaces with high spin polarisation are required for efficient spin injection. In this work we show that thin film of half-metallic full Heusler alloy Co2FeSi0.5Al0.5with uniform thickness and B2 ordering can form structurally abrupt interface with Ge(111). Atomic resolution energy dispersive X-ray spectroscopy reveals that there is a small outdiffusion of Ge into specific atomic planes of the Co2FeSi0.5Al0.5film, limited to a very narrow 1 nm interface region. First-principles calculations show that this selective outdiffusion along the Fe-Si/Al atomic planes does not change the magnetic moment of the film up to the very interface. Polarized neutron reflectivity, x-ray reflectivity and aberration-corrected electron microscopy confirm that this interface is both magnetically and structurally abrupt. Finally, using first-principles calculations we show that this experimentally realised interface structure, terminated by Co-Ge bonds, preserves the high spin polarization at the Co2FeSi0.5Al0.5/Ge interface, hence can be used as a model to study spin injection from half-metals into semiconductors.
authors.affiliation: Department of Physics, University of York, York YO10 5DD, UK.
authors.forename: Zlatko
authors.initials: Z
authors.lastname: Nedelkoski
authors.affiliation: Department of Physics, University of York, York YO10 5DD, UK.
authors.forename: Balati
authors.initials: B
authors.lastname: Kuerbanjiang
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Glover
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Sanchez
authors.affiliation: SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, UK.
authors.forename: Demie
authors.initials: D
authors.lastname: Kepaptsoglou
authors.affiliation: Department of Physics, University of York, York YO10 5DD, UK.
authors.forename: Arsham
authors.initials: A
authors.lastname: Ghasemi
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Burrows
authors.affiliation: Center for Spintronics Research Network, Osaka University, Osaka 560-8531, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Center for Spintronics Research Network, Osaka University, Osaka 560-8531, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hamaya
authors.affiliation: SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, UK.
authors.forename: Quentin M
authors.initials: QM
authors.lastname: Ramasse
authors.affiliation: Department of Physics, University of York, York YO10 5DD, UK.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Hasnip
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hase
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Gavin R
authors.initials: GR
authors.lastname: Bell
authors.affiliation: Department of Electronics, University of York, York YO10 5DD, UK.
authors.forename: Atsufumi
authors.initials: A
authors.lastname: Hirohata
authors.affiliation: Department of Physics, University of York, York YO10 5DD, UK.
authors.forename: Vlado K
authors.initials: VK
authors.lastname: Lazarov