Driving the persistent spin helix and electron-hole density waves with an electric field in n-GaAs quantum wells

ORAL

Abstract

We use transient spin grating spectroscopy to study the persistent spin helix (PSH) state of a 2D electron gas in the presence of an in-plane electric field parallel to the wavevector of the spin helix. By directly measuring its phase, we can measure the PSH displacement with 10 nm spatial and sub-picosecond time resolution. We demonstrate that the phase velocity of the PSH crosses zero at a nonzero wavevector. The data indicate that spin Coulomb drag may play a role in the spin wave drifting process. We also study the displacement of electron-hole density waves (EHDW's) as a function of electric field. Although charge neutral, the EHDW is found to drift, but with with a velocity that is much smaller than that of the surrounding electrons. We speculate that the drift is caused by a Coulomb drag interaction between the Fermi sea and the EHDW.

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Authors

  • Lu-Yi Yang

    • Lawrence Berkeley National Laboratory and University of California Berkeley

  • Jake Koralek

    • Lawrence Berkeley National Laboratory and University of California Berkeley

  • J. Orenstein

    • Lawrence Berkeley National Laboratory and University of California Berkeley

  • D. Tibbetts

    • Center for Integrated Nanotechnologies, Sandia National Laboratory

  • J. Reno

    • Center for Integrated Nanotechnologies, Sandia National Laboratory

  • M. Lilly

    • Center for Integrated Nanotechnologies, Sandia National Laboratory

  • S. Mack

    • Center for Spintronics and Quantum Computation, University of California Santa Barbara

  • D.D. Awschalom

    • Center for Spintronics and Quantum Computation, University of California Santa Barbara