Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Spindependent Transport II
MA 18.3: Vortrag
Mittwoch, 28. März 2007, 15:45–16:00, H22
Interface structure and transport properties of Fe3Si/GaAs: An ab initio study — •Heike C. Herper and Peter Entel — Theoretische Physik, Universität Duisburg-Essen, Campus Duisburg, Lotharstr. 1, 47048 Duisburg
Ferromagnets (FM) on half metals have attracted interest as electronic contacts for spin-injection, because of their high Curie temperature and the possible existence of a Schottky barrier, which acts as natural tunnel barrier in reverse-biasing. However, the quality of the interface is essential for successful spin-injection. Recently successful spin-injection has been reported for Fe3Si/GaAs(001), while attempts with pure Fe/GaAs failed due to alloy formation at the interface. Here we investigate the influence of Si on the interface structure, in particular whether alloy formation with GaAs is suppressed. In addition, we study the transport properties of these systems depending on the interface structure.
The electronic and magnetic properties of Fe3Si/GaAs(001) have been investigated within density functional methods employing the Vienna Ab-initio Simulation Package (VASP) by using the Projector Augmented Wave (PAW) method. The exchange correlation functional is described within the GGA+U method to improve the description of localized d-states and correct the calculated band gap of GaAs. The transport properties of Fe3Si/GaAs are obtained from the Kubo-Greenwood equation in combination with a Green’s function method.
This work is supported by the Deutsche Forschungsgemeinschaft (SFB 491).