Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 19: Transport - Nanoelectronics I: Spintronics and Magnetotransport

TT 19.6: Hauptvortrag

Montag, 7. März 2005, 11:30–12:00, TU H3027

Intrinsic Spin Hall Effect — •Shuichi Murakami — Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan

We theoretically predict that the electric field can induce a substantial amount of spin current at room temperature, in p-type semiconductors such as GaAs [1,2]. This spin current is even under time reversal, and can flow without dissipation. It is caused by the topological Berry phase felt by a hole when it traverses the momentum space, and all the filled states below the Fermi level contribute to the spin current. On the other hand, in some band insulators such as PbTe, the charge conductivity vanishes, and the spin Hall current flows without any dissipation; we can call it a spin Hall insulator [3]. We discuss recent experimental observations of this effect. This effect leads to efficient spin injection into semiconductors without the need for metallic ferromagnets, opening up a new possibility for spintronic devices with low power consumption.

This work was done in collaboration with N. Nagaosa and S.-C. Zhang. References: S. Murakami, N. Nagaosa, and S.-C. Zhang, Science 301, 1348 (2003); Phys. Rev. B69, 235206 (2004); Phys. Rev. Lett. 93, 156804 (2004).