Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 37: Quantum Dots and Wires: Optical Properties I (mainly InGaAs Dots)
HL 37.2: Talk
Tuesday, March 27, 2012, 11:00–11:15, ER 164
Phase synchronization of hole spin precessions in InGaAs quantum dots — •Steffen Varwig1, Dennis Barmscheid1, Irina A. Yugova1,2, Alex Greilich1, Alexander Schwan1, Crispin Müller1, Dmitri R. Yakovlev1, Dirk Reuter3, Andreas D. Wieck3, and Manfred Bayer1 — 1Experimentelle Physik II, TU Dortmund, D-44221 Dortmund, Germany — 2Institute of Physics, St. Petersburg State University, 198504 St. Petersburg, Russia — 3Angewandte Festkörperphysik, Ruhr- Universität Bochum, D-44780 Bochum, Germany
The spin of charge carriers in semiconductor quantum dots is a promising candidate for implementing a quantum bit. We study the spin coherence of holes in an ensemble of self-assembled (In,Ga)As/GaAs QDs by optical faraday rotation and ellipticity measurements. With a periodic train of short pump pulses it is possible to overcome the obstacle of fast spin dephasing due to inhomogeneities. The phase of the spin precession in an external magnetic field is thereby synchronized and this leads to constructive interference of the single spin contributions to the measured signal. Thus one can observe the spin coherence on a long time scale, offering the ability to measure the coherence time T2.