Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 26: Quantum Dots and Wires: Quantum Optics I

HL 26.2: Vortrag

Dienstag, 8. März 2016, 10:00–10:15, H16

Dependency of semiconductor quantum dot shape on absorption and pump probe spectra in negatively charged quantum dots — •Matthias Holtkemper, Doris Reiter, and Tilmann Kuhn — Institut für Festkörpertheorie, Universität Münster, 48149 Münster, Germany

Optically operated semiconductor quantum dots (QDs) are promising structures for quantum information, single photon sources and spintronics. In single QD experiments the geometric properties of the QD often play a vital role, however this is experimentally hard to access. Therefore simulations are essential to gain a detailed understanding of the electronic structure and dynamics in QDs in dependence of the QD geometry. We present a systematic analysis of absorption and pump-probe spectra for negatively charged QDs. To be specific, we model a negatively charged CdSe QD using a configuration interaction approach with a harmonic confining potential and include the direct Coulomb interaction as well as the short-range Coulomb exchange interaction (SRE). We calculate trion and charged biexciton states and compute the dynamics after a pump pulse using a Lindblad model. We discuss trends in the spectra caused by a variation of QD volume, asymmetry and height but also of the SRE strength and the difference between electron and hole confinement length. Our results enable us to extract geometric information about a QD from its absorption spectrum.