Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.31: Poster
Donnerstag, 17. März 2011, 18:00–21:00, P4
Spin dephasing anisotropy in two-dimensional electron systems: dependence on temperature and quantum well width — •Michael Griesbeck1, Dominik Waller1, Gerd Plechinger1, Elisabeth Leierseder1, Tobias Korn1, Dieter Schuh1, Werner Wegscheider1,2, and Christian Schüller1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany — 2present adress: Laboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich, Switzerland
The spin dynamics in most AlGaAs/GaAs-based two-dimensional electron systems are governed by the D’yakonov-Perel spin dephasing mechanism, which results from the underlying spin-orbit (SO) fields. In samples with an asymmetric growth profile, there are contributions to the effective internal SO fields mainly due to the lack of inversion symmetry of the crystal structure, as well as the built-in electric field caused by the asymmetric band profile. The different symmetries of the Dresselhaus and Rashba SO fields lead to the well-known spin dephasing anisotropy (SDA), where the spin dephasing time strongly depends on the spin orientation. In this study we have investigated the temperature dependence of the SDA in samples with different quantum well width, ranging from 10 nm to 25 nm. By means of time-resolved Kerr rotation technique we were able to determine the relative strengths of Dresselhaus and Rashba SO fields from liquid Helium temperature up to 130 K, including the interesting case, where the two contributions have the same strength. Such a system could be a working base of the proposed non-ballistic spin-FET.