Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 68: Spintronics II (HL jointly with MA, O, TT)
O 68.4: Talk
Thursday, April 3, 2014, 10:45–11:00, POT 151
Time- and space-resolved measurements of spin diffusion in high-mobility GaAs-based 2D electron systems — •Markus Schwemmer1, Roland Voelkl1, Tobias Korn1, Sergey Tarasenko2, Dieter Schuh1, Werner Wegscheider3, and Christian Schüller1 — 1Institute of Experimental and Applied Physics, Faculty of Physics,University of Regensburg, Germany — 2A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia — 3ETH Zurich, Switzerland
Two-dimensional electron systems embedded in (110)-grown, symmetrically doped GaAs/AlGaAs QWs are highly interesting for spintronics. They combine high carrier mobility with long spin dephasing times. Previously, we have studied these systems in different experiments, which either gave temporal or spatial resolution. By using a two-beam Hanle-MOKE method we could observe diffusion lengths of more than 125 µm at low temperatures. As a next step, the experimental setup was modified in order to achieve temporal and spatial resolution with the help of a single pulsed TiSa laser. The main issue is the spectral separation of the pump and the probe beams, which are collinearly focused onto the sample. Due to the broad spectrum of the femtosecond laser pulse, this can be realized using bandpass filters. Besides the mapping of the temporal propagation of the spins via diffusion, this experimental setup should also allow to visualize the evolution of a drifting spin packet. Financial support by the DFG via SFB 689 and SPP 1285 is gratefully acknowledged.