Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 71: Quantum Dots and Wires: Optical Properties

HL 71.8: Vortrag

Donnerstag, 10. März 2016, 11:45–12:00, H15

Spin-lattice relaxation time of InGaAs quantum dots — •Daniel A. Lübke¹, Evgeny A. Zhukov¹, Alex Greilich¹, Erik Kirstein¹, Fabian Heisterkamp¹, Tomasz Kazimierczuk¹, Vladimir L. Korenev^1,2, Dirk Reuter³, Andreas D. Wieck³, Dmitri R. Yakovlev^1,2, and Manfred Bayer^1,2 — ¹Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany — ²Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia — ³Angewandte Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany

We demonstrate measurements of the spin relaxation time (T₁) of resident electrons and holes in ensembles of InGaAs quantum dots. These measurements are done using a new method exploiting the spin inertia, based on the pump-probe type of measurements. Here the helicity of the pump laser is switched between both circular polarizations with variable frequency, at fixed pump-probe delay. At low frequencies of modulation, the created spin polarization is able to reach its steady state value, the maximal signal. If the pump helicity changes faster, so that the spin polarization cannot reach its steady state, it results in a decreased signal. We use this technique to evaluate the T₁ time in dependence on the longitudinal magnetic field in the range of ± 300 mT.