Observation of sixfold degenerate fermions in a superconducting metal.

ORAL

Abstract

Condensed matter systems offer a unique platform to study fermions from high energy physics. It is well-known that Dirac and Weyl fermions with four- and twofold degeneracy were visualized in topological quantum materials recently. Beyond these fundamental fermions in high energy physics, it has been proposed that crystal and time-reversal symmetries in solids can also protect three-, six- and eightfold degenerate band crossings. These exotic fermions have no high energy analogues due to Poincare invariance. In this talk, I will present our ultrahigh resolution photoemission study on a superconducting metal that hosts three doubly degenerate quadratic bands at the R point, demonstrating a topological fermion beyond the constraints of high energy physics.

*This work was supported by DOE via Grant No. DOE/BES DEFG-02-05ER46200, Contract No. DE-AC02-76SF00515 and EPSCoR Grant No. DESC0012432 with additional support from the Louisiana Board of Regents.

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Presenters

  • Xian Yang

    • Princeton University
    • Department of Physics, Princeton University

Authors

  • Xian Yang

    • Princeton University
    • Department of Physics, Princeton University

  • Tyler Cochran

    • Princeton University
    • Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University
    • Department of Physics, Princeton University

  • Ramakanta Chapai

    • Louisiana State University

  • Damien Tristant

    • Louisiana State University

  • Jiaxin Yin

    • Princeton University
    • Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University
    • Department of Physics, Princeton University

  • Ilya Belopolski

    • Princeton University
    • Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University
    • Department of Physics, Princeton University
    • Center for Emergent Matter Science, RIKEN

  • Zijia Cheng

    • Princeton University
    • Department of Physics, Princeton University

  • Daniel Multer

    • Princeton University
    • Department of Physics, Princeton University

  • Ilya Vekhter

    • Physics and Astronomy, Louisiana State University
    • Louisiana State University

  • William A Shelton

    • Cain Department of Chemical Engineering, Louisiana State University
    • Louisiana State University

  • Rongying Jin

    • Louisiana State University, Department of Physics and Astronomy
    • Louisiana State University
    • Physics and Astronomy, Louisiana State University

  • Suyang Xu

    • Department of Chemistry and Chemical Biology, Harvard University
    • Havard University
    • Harvard University

  • Zahid Hasan

    • Princeton University
    • Laboratory for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University