Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 44: Poster Session: Quantum Dots and Wires - Transport & Optical Properties
HL 44.14: Poster
Dienstag, 27. März 2012, 09:30–12:30, Poster D
Effects of longitudinal acoustic phonons to the long-time dynamics in optically driven GaAs quantum dots — •Sebastian Lüker1, Doris Reiter1, Vollrath Martin Axt2, and Tilmann Kuhn1 — 1Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster — 2Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth
Semiconductor quantum dots are of great importance both for the investigation of fundamental quantum effects and for future optoelectronic applications. We discuss the laser-induced long-time dynamics in a GaAs quantum dot coupled to longitudinal acoustic phonons. In the strong confinement limit we model the quantum dot as a two level system. To study the dynamics of this system we use the density matrix formalism. The many particle nature of the system due to carrier-phonon interaction leads to an infinite hierarchie of equations of motion which we truncate by a fourth order correlation expansion. In the limit of long times the two level system reaches a stationary state close to a thermal distribution of the dressed states as a result of the interaction with phonons. We discuss the influence of external parameters, in particular temperature and intensity of the laser-field, on the state in the long-time limit. Furthermore we analyze the energy flow between the subsystems during the dynamics, revealing details about the role of the phonons. When comparing our results to a numerically exact real-time path integral method, which may act as a benchmark, we find a good agreement in a surprisingly wide range of parameters [M. Glässl, S. Lüker et al., Phys. Rev. B 84, 195311 (2011)].