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  • Letter
  • Open Access

Observation of gapped Dirac magnons in a Co bilayer grown on Ru(0001)

Khalil Zakeri1,*, Arthur Ernst2,3,4, and Christopher Hins1

  • *Contact author: khalil.zakeri@partner.kit.edu
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Phys. Rev. B 114, L200405 – Published 27 October, 2026

DOI: https://doi.org/10.1103/cprf-rwsn

Abstract

Beyond their fundamental interest in exploring bosonic Dirac physics, Dirac magnons hold potential for the development of efficient spin-transport devices. Here, we demonstrate the experimental realization of gapped terahertz Dirac magnons in an epitaxial Co bilayer on Ru(0001) using spin-polarized electron spectroscopy. Supported by first-principles calculations, we show that although the substrate breaks sublattice symmetry, thereby opening a gap at the K¯ points, the local valley topology is preserved. This is evidenced by a spectral weight redistribution, valley-centered curvature concentrations, and a nonzero local Berry phase. Our results establish the interface as a tuning parameter, paving the way for engineering Dirac magnons in a variety of simple ultrathin bilayer magnets.

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References (73)

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Phys. Rev. B 114, L200405– Published 27 October, 2026
  • Received 23 February 2026
  • Revised 1 October 2026
  • Accepted 9 October 2026
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