804 research outputs found
Spin orientation of two-dimensional electron gas under intraband optical pumping
The theory of spin orientation of two-dimensional (2D) electron gas has been
developed for intrasubband indirect optical transitions. The monopolar optical
orientation of electrons in the conduction band is caused by the indirect
scattering with virtual intermediate states in the valence band and allowance
for selection rules for interband transitions. The considered mechanism of
optical orientation is shown to be in an inherent relation with the special
Elliot-Yafet mechanism of electron spin relaxation induced by virtual interband
scattering.Comment: 3 pages, 2 figures, Symposium "Nanostructures: Physics and
Technology", St.Petersburg, Russia, 200
Direct current driven by ac electric field in quantum wells
It is shown that the excitation of charge carriers by ac electric field with
zero average driving leads to a direct electric current in quantum well
structures. The current emerges for both linear and circular polarization of
the ac electric field and depends on the field polarization and frequency. We
present a micoscopic model and an analytical theory of such a nonlinear
electron transport in quantum wells with structure inversion asymmetry. In such
systems, dc current is induced by ac electric field which has both the in-plane
and out-of-plane components. The ac field polarized in the interface plane
gives rise to a direct current if the quantum well is subjected to an in-plane
static magnetic field.Comment: 6 pages, 3 figure
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