Magnetic electron lensing in the 3D Dirac semi-metal Cd<sub>3</sub>As<sub>2</sub>

ORAL

Abstract

While electrons moving perpendicular to a magnetic field are confined to cyclotron orbits, they can move freely parallel to the field. This simple fact leads to complex current flow in clean, low carrier density semi-metals, such as current jets along the magnetic field when currents pass through point-like constrictions. Occurring accidentally at imperfect current injection contacts, "current jetting" plagues the research of longitudinal magnetoresistance. We demonstrate the controlled generation of tightly focused electron beams in a new class of microdevices machined from crystals of the Dirac semi-metal Cd3As2. The current beams can be guided by tilting an in-plane magnetic field and their range tuned by the field strength. Finite element simulations quantitatively capture the voltage induced at faraway contacts when the beams are steered towards them, supporting the picture of controlled electron jets. These experiments demonstrate the first direct control over the highly non-local signal propagation unique to 3D semi-metals in the current jetting regime.

*This project was funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (“MiTopMat” - grant agreement No. 715730).

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Presenters

  • Philip Moll

    • Institute of Material Science and Engineering, Ecole Polytechnique Federale de Lausanne
    • Ecole Polytechnique Federale de Lausanne
    • École Polytechnique Fédéral de Lausanne
    • Institute of Materials (IMX), EPFL
    • Ecole polytechnique federale de Lausanne

Authors

  • Xiangwei Huang

    • Ecole Polytechnique Federale de Lausanne

  • Carsten Putzke

    • Institute of Material Science and Engineering, Ecole Polytechnique Federale de Lausanne
    • Ecole Polytechnique Federale de Lausanne
    • École Polytechnique Fédéral de Lausanne
    • University of Bristol

  • Chunyu Guo

    • Institute of Material Science and Engineering, Ecole Polytechnique Federale de Lausanne
    • Ecole Polytechnique Federale de Lausanne

  • Jonas Diaz

    • Ecole Polytechnique Federale de Lausanne
    • National High Magnetic Field Laboratory

  • Markus Koenig

    • Max-Planck-Institute for Chemical Physics of Solids
    • Max Planck Institut for Chemical Physics of Solids
    • Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
    • Max Planck Institute for Chemical Physics of Solids

  • Horst Borrmann

    • Max-Planck-Institute for Chemical Physics of Solids
    • MPI-CPfS Dresden
    • Max Planck Institute for Chemical Physics of Solids
    • MPI, Dresden

  • Nityan Nair

    • University of California, Berkeley
    • Department of Physics, University of California, Berkeley
    • physics, University of California, Berkeley

  • James Analytis

    • University of California, Berkeley
    • Department of Physics, University of California, Berkeley
    • Physics, University of California Berkeley
    • Physics, University of California Berkerley
    • Physics, University of California, Berkeley
    • physics, University of California, Berkeley

  • Philip Moll

    • Institute of Material Science and Engineering, Ecole Polytechnique Federale de Lausanne
    • Ecole Polytechnique Federale de Lausanne
    • École Polytechnique Fédéral de Lausanne
    • Institute of Materials (IMX), EPFL
    • Ecole polytechnique federale de Lausanne