Probing Dirac Fermions in Bi-based Semimetals by Cryomagnetic Scanning Tunneling and Point Contact Spectroscopy

ORAL

Abstract

The topological semimetal Bi$_2$Se$_3$ is distinguished by the presence of two-dimensional Dirac fermions with strong spin-orbit coupling. The linear dispersion of Dirac fermions in Bi$_2$Se$_3$ was recently observed by scanning tunneling spectroscopy measurements of the Landau level spacing versus magnetic field. In this work we extend the field-dependent spectroscopy study of Dirac fermions to other Bi-based semimetals, for both topological and non-topological cases, using cryomagnetic scanning tunneling and point contact probes on single crystals down to 300 mK and up to 9 T. The spectral dependences on field strength and field direction are examined, in an effort to elucidate the role of spin-orbit coupling in each case.

*Work supported by: NSERC, CFI-OIT and the Canadian Institute for Advanced Research. Work at Brookhaven supported by: the U.S. DOE under Contract No. DE-AC02-98CH10886 and in part by the Center for Emergent Superconductivity, an Energy Frontier Research.

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Authors

  • John Wei

    • University of Toronto and Canadian Institute for Advanced Research
    • University of Toronto

  • Igor Fridman

    • University of Toronto

  • Y.T. Yen

    • University of Toronto

  • Hechang Lei

    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory

  • Kefeng Wang

    • Brookhaven National Laboratory

  • Cedomir Petrovic

    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory