Multiple Dirac Nodes and Symmetry Protected Dirac Nodal Lines in Orthorhombic α-RhSi

ORAL

Abstract

Exotic multifold topological excitations have been predicted and were recently observed in transition metal silicides like β-RhSi. We report that interesting topological features of RhSi are also observed in its orthorhombic α phase, which displays multiple types of Dirac nodes very close to the Fermi level εF . We discuss the symmetry analysis, band connectivity along high-symmetry lines using group representations, band structure, the nature of the Dirac points and of a nodal line occurring near εF which is protected by the crystalline symmetry. The de Haas–van Alphen effect indicates a Fermi surface in agreement with the calculations. We find an elliptically shaped nodal line very close to εF around and near the S point on the ky-kz plane that results from the intersection of two upside-down Dirac cones. Both Dirac points of the participating Kramers degenerate bands are only 5 meV apart; hence, an accessible magnetic field might induce a crossing between Dirac sub-bands.

*L.B. acknowledges supported from DOE-BES and S.M. from the FSU Provost Postdoctoral Fellowship Program. The National High Magnetic Field Laboratory acknowledges support from US NSF Cooperative Agreement Grant No. DMR-1644779 and the state of Florida.

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Presenters

  • Shirin Mozaffari

    • National High Magnetic Field Laboratory

Authors

  • Shirin Mozaffari

    • National High Magnetic Field Laboratory

  • Niraj Aryal

    • National High Magnetic Field Laboratory

  • Rico Schöenemann,

    • National High Magnetic Field Laboratory
    • Los Alamos National Laboratory

  • Kuan Wen Chen

    • National High Magnetic Field Laboratory

  • Gregory McCandless

    • Chemistry, University of Texas at Dallas
    • Department of Chemistry & Biochemistry, University of Texas at Dallas

  • Julia Y Chan

    • Chemistry, University of Texas Dallas
    • Chemistry, University of Texas at Dallas
    • Department of Chemistry & Biochemistry, University of Texas at Dallas

  • Efstratios Manousakis

    • Florida State University
    • Physics, Florida State University
    • National High Magnetic Field Laboratory, Florida State University

  • Luis Balicas

    • National High Magnetic Field Laboratory
    • National High Magnetic Field Laboratory, Florida State University
    • National High Magnetic Field Lab
    • Condensed Matter Science, National High Magnetic Field Laboratory