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arXiv · 1503.06950

Voltage induced conversion of helical to uniform nuclear spin polarization in a quantum wire

Viktoriia Kornich·Peter Stano·Alexander A. Zyuzin·Daniel Loss
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Abstract

We study the effect of bias voltage on the nuclear spin polarization of a ballistic wire, which contains electrons and nuclei interacting via hyperfine interaction. In equilibrium, the localized nuclear spins are helically polarized due to the electron-mediated Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. Focusing here on non-equilibrium, we find that an applied bias voltage induces a uniform polarization, from both helically polarized and unpolarized spins available for spin flips. Once a macroscopic uniform polarization in the nuclei is established, the nuclear spin helix rotates with frequency proportional to the uniform polarization. The uniform nuclear spin polarization monotonically increases as a function of both voltage and temperature, reflecting a thermal activation behavior. Our predictions offer specific ways to test experimentally the presence of a nuclear spin helix polarization in semiconducting quantum wires.

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Viktoriia Kornich, Peter Stano, Alexander A. Zyuzin, Daniel Loss. 2015-03-29. Voltage induced conversion of helical to uniform nuclear spin polarization in a quantum wire. https://doi.org/10.1103/physrevb.91.195423

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