NdAlSi, a type II magnetic Weyl semimetal

ORAL

Abstract

The combination of type-II Weyl semimetal and the coexistence of broken time-reversal symmetry and inversion symmetry is highly unusual. RAlX materials (R = rare earth, X = Si, Ge) have recently attracted much attention as rare examples of such materials. We focus on NdAlSi due to its interesting magnetic and electronic properties. It shows multiple magnetic phase transitions mediated by RKKY-type interactions with ferromagnetism at 7.2 K and ferrimagnetism (up-up-down Nd spin ordering) at 3.3 K. Using first-principles density-functional theory, we find 20 pairs of Weyl nodes in the paramagnetic phase, 28 pairs of Weyl nodes in the ferromagnetic phase, and 26 pairs of Weyl nodes in the antiferromagnetic phase. We also focus on the Fermi surfaces associated with the Weyl nodes hosting a nesting vector consistent with the experimentally observed magnetic ordering at q ~ [2/3,2/3,0]. Our work exposing the connections between the Weyl node structure and the magnetic ordering should be applicable to this class of materials more broadly, stimulating further interest in their remarkable properties.

*This work was supported by the Institute for Quantum Matter under DOE EFRC grant DE-SC0019331.

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Presenters

  • Santu Baidya

    • Rutgers University
    • Rutgers University, New Brunswick
    • Department of Physics and Astronomy, Rutgers University

Authors

  • Santu Baidya

    • Rutgers University
    • Rutgers University, New Brunswick
    • Department of Physics and Astronomy, Rutgers University

  • David Vanderbilt

    • Rutgers University, New Brunswick
    • Rutgers University
    • Physics, Rutger Univeristy
    • Department of Physics and Astronomy, Rutgers University
    • Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA

  • Jonathan Gaudet

    • Department of Physics and Astronomy and Institute for Quantum Matter, The Johns Hopkins University
    • Johns Hopkins University
    • Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA

  • Hung-Yu Yang

    • Department of Physics, Boston College
    • Boston College
    • Department of Physics, Boston College, Chestnut Hill, MA 02467, USA

  • Fazel Tafti

    • Boston College
    • Department of Physics, Boston College
    • Department of Physics, Boston College, Chestnut Hill, MA 02467, USA

  • Collin Leslie Broholm

    • Johns Hopkins University
    • Department of Physics and Astronomy and Institute for Quantum Matter, The Johns Hopkins University
    • Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University
    • Physics, The Johns Hopkins University