Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 49: Spinabh
ängiger Transport III

HL 49.1: Vortrag

Freitag, 12. März 2004, 11:00–11:15, H13

Spin-Hall effect and anisotropic charge transport in semiconductors — •John Schliemann, J. Carlos Egues, and Daniel Loss — Department of Physics and Astronomy, University of Basel, Switzerland

In a two-dimensional electron gas as realized by a semiconductor quantum well, the presence of spin-orbit coupling of both the Rashba and Dresselhaus type leads to anisotropic dispersion relations and Fermi contours. We study the effect of this anisotropy on the electrical conductivity in the presence of fixed impurity scatterers. The conductivity also shows in general an anisotropy which can be tuned by varying the Rashba coefficient. This effect provides a method of detecting and investigating spin-orbit coupling by measuring spin-unpolarized electrical currents in the diffusive regime.

Moreover, we investigate the spin-Hall effect of both electrons and holes in semiconductors using the Kubo formula in the correct zero-frequency limit taking into account the finite momentum relaxation time of carriers in real semiconductors. This approach allows to analyze the range of validity of recent theoretical findings. In particular, the spin-Hall conductivity vanishes for vanishing spin-orbit coupling if the correct zero-frequency limit is performed.

References: J. Schliemann, J. C. Egues, and D. Loss, Phys. Rev. Lett. 90, 146801 (2003).

J. Schliemann and D. Loss, Phys. Rev. B 68, 165311 (2003).

J. Schliemann and D. Loss, cond-mat/0310108.