Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 19: Transport - Nanoelectronics I: Spintronics and Magnetotransport
TT 19.7: Vortrag
Montag, 7. März 2005, 12:00–12:15, TU H3027
Spin Hall conductivity of a two dimensional electron gas — •Peter Schwab1 and Roberto Raimondi2 — 1Institut für Physik, Universität Augsburg, 86135 Augsburg — 2Dipartimento di Fisica, Università di Roma Tre, 00146 Roma, Italy
In a two-dimensional electron gas with spin orbit couping an electric field applied in the x-direction in the plane induces a spin current in the y-direction with the spins polarized perpendicular to the plane. Over the last year this so-called spin Hall effect has attracted a lot of attention due to possible applications in spintronics.
We calculate the spin Hall conductivity
σxy(ω) for a weakly disordered two-dimensional electron gas, varying both the strength and type of disorder. In the static limit, i.e.
for frequencies that are below the elastic scattering rate, we find a vanishing
spin Hall conductivity, independent of the type of disorder.
The spin Hall conductivity vanishes due to a cancellation between a reactive
contribution to the conductivity σreact= e/8π whose universal value is related to a Berry phase, and a dissipative contribution
σdiss= −e/8π.
[1] S. Murakami, N. Nagaosa, and S.-C. Zhang, Science 301, 1348 (2003); J. Sinova, D. Culcer, Q. Niu, N. A. Sinitsy, T. Jungwirth, and A. H. MacDonald, Phys. Rev. Lett. 92, 126603 (2004).
[2] R. Raimondi and P. Schwab, cond-mat/0408233.