Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 39: Ultra fast phenomena
HL 39.1: Talk
Thursday, February 28, 2008, 11:15–11:30, ER 270
Intensity dependence of charge and spin currents generated by ultrafast two-color photoexcitation*of semiconductor quantum wells — Bernhard Pasenow1, Huynh Thanh Duc2,1, •Torsten Meier3,1, and Stephan W. Koch1 — 1Department of Physics and Material Sciences Center, Philipps University, Renthof 5, D-35032 Marburg, Germany — 2Ho Chi Minh City Institute of Physics, Viet Nam Center for Natural Science and Technology,*1 Mac Dinh Chi, Ho Chi Minh City, Vietnam — 3Department Physik, Fakultät für Naturwissenschaften, Universität Paderborn, Warburger Str. 100, D-33098 Paderborn, Germany
Charge and spin currents that are generated on ultrafast time scales
by two-color laser excitation of semiconductor quantum wells are computed
using Bloch equations that formulated in the basis of k · p wave
functions [1,2].
The optically induced inter- and intraband excitations are both treated
nonperturbatively providing a consistent description of phototransport effects
in the high-excitation regime.
The analysis shows that the photoexcited charge and spin currents depend on the
amplitudes of the incident ω and 2ω beams in a highly nonlinear fashion.
It is predicted that Rabi flopping leads to
intensity-dependent changes of the current directions [3].
[1] B. Pasenow, Dissertation, Philipps-University Marburg, 2006.
[2] T. Meier, B. Pasenow, H.T. Duc, Q.T. Vu, H. Haug, and S.W. Koch,
Proc. of SPIE 6471, 647108 (2007).
[3] B. Pasenow, H.T. Duc, T. Meier, and S.W. Koch,
Solid State Communications, in press.