Regensburg 2000 – wissenschaftliches Programm

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SYUO: Ultrakurzzeitdynamik an Oberflächen

SYUO 4: Ultrakurzzeitdynamik III (1)

SYUO 4.1: Hauptvortrag

Donnerstag, 30. März 2000, 14:30–15:00, H45

Microscopic Theory of Dephasing in Semiconductors — •Stephan W. Koch — Fachbereich Physik, Philipps-Universität Marburg, Renthof 5, 35032 Marburg

This talk presents an overview of a microscopic theory for the near bandgap optical response of semiconductors. At the coherent (Hartree-Fock) level Coulomb interaction effects of the excited electron-hole pairs lead to renormalization of the transition energy and the effective field. A systematic analysis of correlation contributions beyond the Hartree-Fock level makes it possible to study interaction induced dephasing in pump-probe or four-wave mixing configurations. For realistic quantum-well systems with structural disorder, e.g. due to interface roughness or composition fluctuations, it is shown that the interplay between disorder and Coulomb correlation effects leads to polarization dependent dephasing.