Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 33: Poster I: Transport, including Magnetic-Field Effects
HL 33.11: Poster
Dienstag, 23. März 2010, 18:30–20:30, Poster D1
Spin photocurrents in diluted magnetic semiconductors — •M. Schmalzbauer1, P. Olbrich1, S.D. Ganichev1, S.A. Tarasenko2, V.V. Bel’kov2, Ch. Brinsteiner1, W. Eder1, D.R. Yakovlev2,3, V. Kolkovsky4, W. Zaleszczyk4, G. Karczewski4, T. Wojtowicz4, and D. Weiss1 — 1THz Center, University of Regensburg, Germany — 2Ioffe Physico-Technical Institute, Rus. Academy of Sciences, St. Petersburg, Russia — 3Exp. Physics 2, TU Dortmund, Germany — 4Institute of Physics, Warsaw, Poland
We report on the observation of spin photocurrents resulting from the zero-bias spin separation in diluted magnetic semiconductors (DMS). We show that in (001)-grown (Cd,Mn)Te/(Cd,Mg)Te quantum wells the absorption of THz radiation leads to pure spin currents. Although the electric current is zero, spin up and down carriers pile up on opposed sample edges. By means of an in plane magnetic field B the balance between the spin currents is disturbed due to the Zeeman splitting and leads to a electron flow increasing with B. In DMS this conversion is strongly enhanced due to the giant Zeeman splitting and the spin-dependent exchange scattering of e− by Mn2+ ions polarized in the external magnetic field [1]. Both contributions affect the balance between the contrarily spin flows additionally and give rise to the electric current. For weak B and a degenerated 2DEG the scattering mechanism dominates the conversion. We demonstrate the importance of the spin-dependent scattering in the current generation giving an additional access to the manipulation of spin-polarized currents.
[1] S.D. Ganichev et. al., Phys. Rev. Lett. 102, 156602 (2009)