Regensburg 2004 – scientific programme
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MA: Magnetismus
MA 27: Spinabh
ängiger Transport II
MA 27.2: Talk
Thursday, March 11, 2004, 15:30–15:45, H22
An ab-initio embedded Green function formulation of spin-dependent electron transport — •Stefan Blügel1, Daniel Wortmann1,2, and Hiroshi Ishida3 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich — 2Research Institute for Computational Sciences, AIST, Tsukuba, Japan — 3College of Humanities and Sciences, Nihon-University, Tokyo, Japan
Parallel to the recent experimental progress in the fabrication of nanostructures, the theoretical investigation of spin-dependent transport in such systems became a focus field of research. Different schemes extending the application of electronic structure calculations using the density-functional theory (DFT) have been proposed to describe transport within the independent particle picture of the Kohn-Sham eigenstates.
Following the same idea we will demonstrate a new approach starting from the description of a scattering volume sandwiched between two semi-infinite leads. Using the embedding method, the Green function of this scattering region can be evaluated enabling us to obtain the conductance. Different formulations of transport will be compared and the extension of the formalism taking into account the non-linear effect of a finite applied bias using the non-equilibrium Green function formulation will be presented. The actual implementation is based on the FLEUR code and the full-potential linearized augmented plane method. Results of the code applied to model systems as well as to the Fe/MgO/Fe tunnel-magneto-resistance (TMR) junction will be shown.