Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 26: III-V semiconductors I
HL 26.9: Vortrag
Dienstag, 26. Februar 2008, 17:45–18:00, EW 202
Current-induced spin polarization (CISP) in InGaAs monitored by Faraday-microscopy — •A. Müller1,3, S. Glatthaar1,3, S. Goebbels1,3, K. Schmalbuch1,3, B. Beschoten1,3, G. Güntherodt1,3, M. Hagedorn2,3, and T. Schäpers2,3 — 1II. Physikalisches Institut, RWTH Aachen, Templergraben 55, 52056 Aachen — 2Institut für Bio- und Nanosysteme IBN-1, Forschungszentrum Jülich, 52425 Jülich — 3Virtuelles Institut für Spinelektronik (VISel), Aachen-Jülich-Göttingen
Most prominent methods to create spin-polarised carriers in semiconductors include optical orientation and electrical spin injection from a ferromagnetic electrode. A novel electrical method to create spin-polarised carriers without electric or magnetic fields has recently been demonstrated by Kato et al. [1]. The so-called Current-Induced-Spin-Polarisation (CISP) as observed in InGaAs is related to internal electric fields as a result of crystal strain in the material. We investigate the steady state spin polarisation in 160 µm wide Si-doped InGaAs channels grown on GaAs, with a cw laser using a high resolution Faraday microscope in Voigt geometry. Hanle images of the CISP are systematically acquired as a function of voltage, magnetic field, and temperature. Information on the spin dephasing times and the spatial homogeneity of the CISP is extracted from these measurements. Surprisingly, we observe symmetric Hanle curves in contrast to results by Kato et al. [1], demonstrating that the spins are oriented in the out-of-plane direction.
[1] Y. K. Kato et al., PRL 93, 176601 (2004)
Work supported by DFG through SPP 1285 and by HGF