Current-induced spin polarization in anisotropic spin-orbit fields

ORAL

Abstract

Current-induced spin polarization is a phenomenon in which carrier spins are oriented when subjected to current flow. As an all-electrical means of aligning spins it has the potential to be useful for spintronics applications. However, the mechanism that produces this spin polarization remains an open question. Measurements are taken on strained In$_{0.04}$Ga$_{0.96}$As exhibiting a spin-orbit interaction that is anisotropic in momentum\footnote{B. M. Norman, C. J. Trowbridge, D. D. Awschalom, and V. Sih, ``Current-induced spin polarization in anisotropic spin-orbit fields,'' submitted.}. We pattern contacts such that electrical conduction can be oriented along any in-plane direction. By varying the electron current direction we can continuously tune between the spin-orbit field extrema. We show that, contrary to expectation, the magnitude of the current-induced spin polarization decreases with increasing spin-orbit field. Furthermore, we find that the steady-state in-plane spin polarization is not along the direction of the spin-orbit field, except in the cases that the spin-orbit field is along an eigenvector of the spin relaxation tensor.

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Authors

  • Benjamin Norman

    Department of Physics, University of Michigan, Ann Arbor, MI 48109

  • Christopher Trowbridge

    Department of Physics, University of Michigan, Ann Arbor, MI 48109

  • D.D. Awschalom

    University of Chicago and UC Santa Barbara, Institute for Molecular Engineering, University of Chicago, Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637, Institute for Molecular Engineering, University of Chicago, Chicago, IL 60652, Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA, 93106, University of Chicago - Institute for Molecular Engineering, Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106, USA

  • Vanessa Sih

    Univ of Michigan - Ann Arbor, Department of Physics, University of Michigan, Ann Arbor, MI 48109