Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 95: Poster IV B (Quantum dots and wires: Prepration, characterization, optical properties, and transport)

HL 95.13: Poster

Donnerstag, 19. März 2015, 14:00–20:00, Poster B

The role of band mixing for excitons and biexcitons in semiconductor quantum dots — •Matthias Holtkemper, Doris E. Reiter, and Tilmann Kuhn — Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

A detailed understanding of the electronic structure in semiconductor quantum dots (QD) is a prerequisite to model dynamical processes in QDs relevant for quantum information processing. We analyse the structure of excitons and biexcitons by studying theoretically the influence of different coupling mechanisms. To be specific, we model the QD using a harmonic confining potential and consider valence band mixing using a four band Luttinger theory, direct Coulomb interaction as well as long- and short-range Coulomb exchange interaction. We discuss the dependence of specific coupling mechanisms on the QD size and shape. We find a different scaling of Luttinger and Coulomb couplings depending on the QD size, while varying the QD shape leads to jumps in Coulomb exchange couplings. Furthermore we extend our studies to a QD doped with a single Mn, where a six line signature on the lowest absorption line appears. The calculated spectrum shows additional features due to the consideration of Luttinger couplings which are in good agreement with experimental findings.