Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 26: III-V semiconductors I
HL 26.8: Vortrag
Dienstag, 26. Februar 2008, 17:30–17:45, EW 202
Intersubband Spin Relaxation Mechanism in n-doped [110] GaAs Quantum Wells — •Lena Schmid1, Shijian Chen1, Stefanie Döhrmann1, Stefan Oertel1, Dieter Schuh2, Werner Wegscheider2, Jens Hübner1, and Michael Oestreich1 — 1Institute for Solid State Physics, Gottfried Wilhelm Leibniz University Hannover, Appelstr. 2, 30167 Hannover, Germany — 2Institute of Experimental and Applied Physics, University of Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
The intersubband spin relaxation mechanism most likely represents the major spin dephasing channel in room temperature applications based upon heterostructures in (110) oriented GaAs for spins oriented along the growth direction.[1] The electron spin relaxation time
τs in n-doped (110) GaAs/AlGaAs quantum wells is investigated by time- and polarisation-resolved photoluminescence measurements in dependence on the subband energy splitting and subband occupancy. The influence by the subband energy splitting on τs is deduced from well width dependent measurements, whereas different occupancies are adjusted by different sample temperatures. The n-doping suppresses the spin dephasing influence of holes created by the optical excitation. The (110) structure suppresses the Dyakonov-Perel relaxation mechanism for spins pointing in growth direction. Therefore the resulting spin relaxation times are long even at room temperature and the intersubband spin relaxation mechanism becomes the dominating spin relaxation mechanism.
[1] S. Döhrmann et al., Phys. Rev. Lett. 93, 147405 (2004))