Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 29: Quantum dots: Optical properties II

HL 29.4: Talk

Wednesday, March 25, 2009, 10:15–10:30, BEY 154

The Influence of Fröhlich-Coupling on Rabi-Oscillations in Semiconductor Quantum Dots — •Kolja Schuh, Jan Seebeck, Paul Gartner, and Frank Jahnke — Institute for Theoretical Physics, University of Bremen, Germany

Rabi-oscillations can be used to switch occupations in a well-defined way and therefore are considered for application in optical switches. Particularly quantum dots have been regarded as possible candidates. The influence of dephasing due to electron-LA-phonon interaction in semiconductor quantum dots was shown in Ref. [1]. In addition to dephasing, this contribution focuses on the influence of scattering processes due to electron-LO-phonon-interaction.

We use a quantum-kinetic many-body theory, where carriers are described as polarons [2]. For quantum-dot states the effective coupling is enhanced, so that there are strong dephasing as well as fast carrier scattering processes even for semiconductors with weak polar coupling. We find that the particle scattering is of particular importance for the switching behaviour as the carrier distribution changes even in the absence of an optical pulse.

[1] J. Förstner et al., Phys. Rev. Lett. 91, 127401 (2003).

[2] J. Seebeck et al., Phys. Rev. B 71, 125327 (2005).