Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster 1
HL 13.29: Poster
Montag, 26. März 2007, 15:00–17:30, Poster A
Formation of Bloch-oscillations and plasma frequency in femtosecond excited semiconductors — •Klaus Morawetz1,2, Pavel Lipavsky3, and Michael Schreiber1 — 1Institute of Physics, Chemnitz University of Technology, *09107 Chemnitz, Germany — 2Max Planck Institute for the Physics of Complex*Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany — 3Faculty of Mathematics and Physics, Charles University, *Ke Karlovu 3, 12116 Prague 2, Czech Republic
Starting from a quantum kinetic equation including the mean field and a conserving relaxation-time approximation we derive an analytic formula which describes the time dependence of the dielectric function in a plasma created by a short intense laser pulse with an additional external electric field bias. This formula reproduces universal features of the formation of collective modes seen in recent experimental data of femtosecond spectroscopy, [Phys. Rev. B 72 (2005) 233203-1-5], and describes the appearance of additional Bloch oscillations due to the finite bias. The long-time limit of the response function coincides with the field-dependent dielectric function derived earlier. [Phys. Rev. E 50 (1994) 474-479]