Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 39: Transport: Nanoelectronics II - Spintronics and Magnetotransport

TT 39.7: Vortrag

Freitag, 29. Februar 2008, 12:15–12:30, EB 202

Photon-assisted spin transport in a two-dimensional electron gas: spin-polarized current and spin valve effect — •Mikhail Fistul¹ and Konstantin Efetov^1,2 — ¹Theoretische Physik III, Ruhr-Universität Bochum, Germany — ²L. D. Landau Institute for Theoretical Physics, Moscow, Russia

We study spin-dependent transport in a two-dimensional electron gas subject to an external step-like potential V(x) and irradiated by an electromagnetic field (EF). In the absence of EF the electronic spectrum splits into spin sub-bands originating from the "Rashba" spin-orbit coupling. We show that the resonant interaction of propagating electrons with the component EF parallel to the barrier induces a non-equilibrium dynamic gap (2Δ _R) between the spin sub-bands. Existence of this gap results in coherent spin-flip processes that lead to a spin-polarized current and a large magnetoresistance, i.e the spin valve effect. These effects may be used for controlling spin transport in semiconducting nanostructures, e.g. spin transistors, spin-blockade devices etc. , by variation of the intensity S and frequency ω of the external radiation.