Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties

HL 91.14: Poster

Thursday, March 14, 2013, 16:00–20:00, Poster A

Excitons in double quantum dots: Phonon effects and spin-orbit coupling — •Jonas Daniels¹, Paweł Machnikowski², and Tilmann Kuhn¹ — ¹Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster — ²Institute of Physics, Wrocław University of Technology, 50-370 Wrocław, Poland

We investigate theoretically excitons in a double quantum dot system. As a function of an external electric field, the absorption spectrum exhibits various anticrossings. These can be attributed to different coupling mechanisms such as tunnel-coupling, Coulomb interaction or spin-orbit coupling. The linewidth of the exciton transitions depends on the interaction of the excitons with the phononic environment, which causes phonon-assisted relaxation as well as phonon-assisted tunneling especially at an anticrossing.

We investigate these phenomena for a pair of lens-shaped vertically aligned InAs/GaAs QDs. A variational method is used to calculate single-particle states, while Coulomb interaction is included within configuration-interaction. We calculate phonon-assisted relaxation rates caused by the deformation-potential coupling to longitudinal-acoustic (LA) phonons and the piezoelectric coupling to LA and transverse-acoustic (TA) phonons. Spin-orbit coupling is considered by the Dresselhaus or k³-term.