Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 34: Poster I: III-V Semiconductors

HL 34.11: Poster

Tuesday, March 23, 2010, 18:30–20:30, Poster D2

Temperature dependent investigation of spin dynamics in a Mn-contaminated AlGaAs/GaAs quantum well near an epitaxial GaMnAs layer — •Sebastian Krinner, Michael Griesbeck, Sebastian Fehringer, Robert Schulz, Tobias Korn, Dieter Schuh, Werner Wegscheider, and Christian Schüller — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany

GaMnAs is a candidate for future semiconductor-based, all electrical spin injection devices. Due to the diffusion of the Mn²⁺ ions, the properties of quantum structures in the vicinity of a GaMnAs layer can be dramatically affected [1]. In our sample, consisting of two nominally undoped AlGaAs/GaAs quantum wells, where one is close to an 50 nm thick GaMnAs layer and the other (as a reference) is separated by a 100 nm AlGaAs barrier, we could observe long spin lifetimes on the order of a few ns and an increase of the spin lifetime with increasing Mn contamination. In this system we observed strong dependences of the spin lifetime on applied inplane magnetic fields, the sample temperature and the excitation intensity, using all optical techniques like time-resolved Kerr rotation (TRKR), time-resolved photoluminescence (TRPL) and the resonant spin amplification technique (RSA). The dependence on temperature and excitation intensity shows that for T > 30 K the system is in the motional narrowing regime of the D’yakonov-Perel mechanism.

[1] R. Schulz et al., Physica E 40, 2163 (2008)