Dresden 2003 – scientific programme
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MA: Magnetismus
MA 30: Spinabh
ängige Transportph
änomene II
MA 30.3: Talk
Friday, March 28, 2003, 11:15–11:30, HSZ/401
Relativistic Effects in the Transport Properties of Ferromagnetic-Semiconductor-Ferromagnetic (FM/SC/FM) Trilayer Systems — •V. Popescu1, H. Ebert1, N. Papanikolaou2, R. Zeller2, and P. H. Dederichs2 — 1Department Chemie/Physikalische Chemie, University of Munich, Butenandtstr. 5-13, 81377 Munich, Germany — 2Inst. für Festkörperforschung, Forschungszentrum Jülich, Postfach 1913, D-52425 Jülich, Germany
Spin-dependent transport between two ferromagnetic electrodes separated by either an insulator or a semiconductor has received a lot of interest in the last years due to its potential technological applications. Recently it could be shown that a measurable spin-polarised injection can be obtained in a TMR Fe/GaAs diode even at room temperature. Many theoretical studies devoted to TMR systems can be found in the literature, but they either neglect relativistic effects or treat the crystalline structure in an approximate way. To allow for a most general description, our present investigations on FM/SC/FM systems have been performed within the framework of Tight-Binding Spin-Polarised Relativistic Multiple Scattering Theory (TB-SPR-KKR). The electronic structure and magnetic properties of Fe/GaAs/Fe as a representative example will be presented. The transport properties of this systems are investigated by means of the Landauer-Büttiker formalism. The tunneling conductance and the TMR are calculated on a relativistic level. Model calculations allow us to gradually manipulate the strength of the spin-orbit coupling (SOC) and to investigate in detail its quantitative and qualitative influence on the spin-dependent transport.