Dynamic nuclear polarization from current-induced electron spin polarization in n-InGaAs

ORAL

Abstract

Control of the nuclear spin system could prove useful for applications in spintronics or spin-based quantum computation for intermediate term data storage and for the suppression of electron spin dephasing resulting from hyperfine coupling. We investigate the role of nuclear spins in materials with electrically generated spin polarization. The electron spin polarization generated by electrical current in a non-magnetic semiconductor is transferred via dynamic nuclear polarization to the nuclei. The resulting nuclear field is interrogated using Larmor magnetometry. We measure the nuclear field as a function of applied magnetic field, current magnitude and direction, and temperature. An unexpected spatial asymmetry in saturated nuclear field is found. The direction of the nuclear polarization is determined by the directions of the electron spin alignment and external magnetic field, allowing electronic control over the sign of the nuclear alignment direction. Careful study of the nuclear field also enables characterization of the current-induced electron spin polarization in situations that are otherwise experimentally inaccessible. Work supported by AFOSR, NSF and ONR.

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Authors

  • Christopher Trowbridge

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

  • Benjamin Norman

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

  • Yuichiro Kato

    Institute of Engineering Innovation, University of Tokyo, Tokyo, Japan

  • 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