Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 37: Quantum Dots and Wires: Optical Properties I (mainly InGaAs Dots)

HL 37.2: Vortrag

Dienstag, 27. März 2012, 11:00–11:15, ER 164

Phase synchronization of hole spin precessions in InGaAs quantum dots — •Steffen Varwig¹, Dennis Barmscheid¹, Irina A. Yugova^1,2, 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.