Tunable All Electric Spin Polarizer Using A Quantum Point Contact With Two Pairs of In-Plane Side Gates

ORAL

Abstract

We report the first experimental investigation of a device consisting of a quantum point contact (QPC) with four gates -- two in-plane side gates in series. The first set of gates (nearest the source contact) is asymmetrically biased to create spin polarization in the channel of the QPC. A symmetric bias is then applied on the second set of side gates (nearest the drain) and varied to tune the location of a conductance anomaly near 0.5 (x2e$^{2}$/h). The experimental results compare well with simulations of the four-gate QPC devices using a Non-Equilibrium Green's Function formalism. The device is shown to be a tunable all-electric spin polarizer. The range of common-mode bias on the first set of gates over which maximum spin polarization can be achieved is much broader for the four-gate structure compared with the case of a QPC with a single pair of in-plane side gates.

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Authors

  • Nikhil Bhandari

    School of Electronics and Computing Systems, University of Cincinnati, Cincinnati, Ohio

  • James Charles

    School of Electronics and Computing Systems, University of Cincinnati, Cincinnati, Ohio

  • Maitreya Dutta

    School of Electronics and Computing Systems, University of Cincinnati, Cincinnati, Ohio

  • Partha Das

    Physics of Nanodevices, Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands,

  • Marc Cahay

    School of Electronics and Computing Systems, University of Cincinnati, Cincinnati, Ohio

  • Richard Newrock

    Physics Department, University of Cincinnati, Cincinnati, Ohio

  • Steven Herbert

    Xavier University, Department of Physics, Xavier University, Cincinnati, Ohio