Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 19: Spin controlled transport I
HL 19.9: Vortrag
Dienstag, 27. März 2007, 12:45–13:00, H14
Spin Photocurrents and Circular Photon Drag Effect in (110)-grown Quantum Well Structures — •H. Diehl1, V. A. Shalygin2, Ch. Hoffmann1, S. N. Danilov1, Th. Herrle1, S. A. Tarasenko3, E. L. Ivchenko3, V. V. Belkov3, D. Schuh1, Ch. Gerl1, W. Wegscheider1, W. Prettl1, and S. D. Ganichev1 — 1Faculty Physics, University of Regensburg, Regensburg, Germany — 2St. Petersburg State Polytechnic University, St. Petersburg, Russia — 3A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia
We report on the observation of spin photocurrents [1] in (110)-grown GaAs/AlGaAs quantum well structures. Investigated effects comprise the circular photogalvanic effect and the circular photon drag effect predicted long time ago but so far not observed. The measurements of photocurrents are carried out by excitation with infrared or terahertz radiation yielding inter-subband transitions between the lowest and the first excited subbands or intra-subband (Drude-like) absorption of the radiation, respectively. The experimental data are well described by analytical expressions derived from a phenomenological theory. The circular photon drag current in the longitudinal direction reverses its sign as the circular polarization of radiation changes from right handed to left handed and is related to transfer of both linear and angular photon momentum to the electron system. A microscopic model of the circular photon drag effect is developed demonstrating that the generated current has spin dependent origin.
[1] S.D. Ganichev and W. Prettl, Intense Terahertz Excitation of Semiconductors, (Oxford University Press, 2006).