Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 19: Spin controlled transport I

HL 19.6: Vortrag

Dienstag, 27. März 2007, 12:00–12:15, H14

Transport experiments on ferromagnet/semiconductor hybrid structures — •Valentin Fedl, Andreas Wittmann, and Dirk Grundler — Physik Department E10, Fakultät für Physik, Technische Universität München, James Franck Str., 85748 Garching

We report transport experiments on ferromagnet/semiconductor hybrid structures. The interface between the two dimensional electron system in InAs and the metal is created by in situ cleavage of the InAs heterostructure followed by thermal evaporation of Fe or Co. Au is taken as a nonmagnetic reference. The InAs/metal interfaces show an Ohmic behavior. To understand the magnetotransport of such hybrid structures we first measure the specific resistance of the metal films as a function of temperature. The data is interpreted using the Fuchs-Sondheimer formalism[1,2]. Second we determine the interface resistance by using the transmission line method[3]. The interface quality is judged through comparison of the experimentally obtained value with the Sharvin resistance[4]. Third we investigate spin injection in mesoscopic devices by exploiting the Hanle effect[5,6]. The aim is to relate the spin injection rate to the interface quality and resistance.

[1] K. Fuchs, Proc. Cambridge Phil. Soc. 34, 100 (1938), [2] E. H. Sondheimer, Advan. Phys. 1, 1 (1952), [3] D. C. Look, Electrical Characterization of GaAs Materials and Devices, John Wiley & Sohns Ltd., Sussex (1989), [4] Yu. V. Sharvin, Sov. Phys. *JETP 21, 655-656 (1965), [5] Johnson & Silsbee, Phys. Rev. B 37, 10 (1987), [6] Lou et al., Phys. Rev. Let. 96, 176603 (2006)