Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 95: Quantum Dots and Wires: Optical Properties III (mainly Cavities and Ultrafast Response)
HL 95.6: Vortrag
Freitag, 30. März 2012, 10:45–11:00, EW 201
Role of Coulomb correlations and carrier relaxation for pump-probe signals obtained from a single quantum dot — •Jan Huneke1,2, Irene D'Amico3, Pawel Machnikowski4, and Tilmann Kuhn2 — 1Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain — 2Institut für Festkörpertheorie, WWU Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany — 3Department of Physics, University of York, Heslington York YO10 5DD, United Kingdom — 4Institute of Physics, Wroclaw University of Technology, PL-50 370 Wroclaw, Poland
We present a theoretical modeling of femtosecond pump-probe experiments performed on a single negatively charged quantum dot. The influence of Coulomb-correlation effects as well as carrier relaxation is investigated. In particular, we study their influence on the fundamental trion absorption line. Our model describes the ultrafast disappearance of the fundamental trion absorption due to instantaneous Coulomb renormalizations and a delayed onset of gain at the same frequency, as found in the measurements[1]. As a result of spin- conserving carrier relaxation, our model predicts the emergence of new optical transitions exhibiting either gain or absorption. The time dependence of these new transitions provides insight into details of the carrier relaxation processes.
[1] F Sotier, T Thomay, T Hanke, J Korger, S Mahapatra, A Frey, K Brunner, R Bratschitsch and A Leitenstorfer, 2009 Nature Physics 5 352