Weyl Magnons in a Non-Coplanar Antiferromagnet

ORAL

Abstract

Building on our recently developed topological magnon materials catalog [1], we explore the first clear realization of the magnonic analog of Weyl electrons in the non-coplanar antiferromagnet MnTe2. Using a combination of band representation analysis, inelastic neutron scattering (INS), magneto-Raman spectroscopy measurements, and linear spin wave theory, we determine that the non-coplanar nature of the antiferromagnetic ordering protects topological magnon nodal lines that breaks into Weyl magnons upon the application of specific symmetry-breaking perturbations. Zero-field INS measurements confirm the existence of the topological magnon nodal lines through the pseudo-spin winding of the scattering intensity in angular scans near the nodal lines, indicating the non-trivial topology of the magnon wavefunctions. Additionally, the emergence of Weyl magnons produces a direct signature on the bulk thermal Hall transport which we prove experimentally to agree with our theoretical predictions. Realizing and controlling Weyl magnons [2], this work allows further exploration of tunable topological behavior in bosonic systems, and highlights the rich interplay between magnetic order and band topology.

[1] Karaki, M.J., Fahmy, A.E., et al. High-throughput discovery of perturbation-induced topological magnons. npj Comput Mater 11, 216 (2025).

[2] Fahmy A.E., et al. Topological nodal Line and Weyl Magnons in the non-coplanar antiferromagnet MnTe2. in preparation.

*This work was primarily funded by the National Science Foundation MRSEC program under grant DMR-2011876 to the Center for Emergent Materials at Ohio State. The identification of any commercial product or trade name does not imply endorsement or recommendation by the National Institute of Standards and Technology. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to SEQUOIA (BL- 17) on proposal number IPTS- 2637.1.

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Publication: Fahmy A.E., et al. Topological nodal Line and Weyl Magnons in the non-coplanar antiferromagnet MnTe2. in preparation.

Presenters

  • Ahmed Emad Fahmy

    • Ohio State University

Authors

  • Ahmed Emad Fahmy

    • Ohio State University

  • Archibald J Williams

    • The Ohio State University

  • Yufei Li

    • Ohio State University

  • Mohamed E Nawwar

    • Ohio State University

  • Thuc Mai

    • AV, AFRL

  • Kevin F Garrity

    • National Institute of Standards and Technology (NIST)

  • Mathew B Stone

    • Oak Ridge National Laboratory

  • Mohammed J Karaki

    • Ohio State University

  • Sara Haravifard

    • Duke University

  • Angela R. Hight Walker

    • National Institute of Standards and Technology (NIST)

  • Rolando Valdes Aguilar

    • Ohio State University

  • Joshua E Goldberger

    • Ohio State Univ - Columbus
    • The Ohio State University

  • Yuanming Lu

    • The Ohio State University
    • Ohio State University

  • Joseph P Heremans

    • Department of Mechanical and Aerospace Engineering, Materials Science and Engineering, and Physics at the Ohio State University
    • The Ohio State University
    • Ohio State University