Magnonic triply-degenerate nodal points

Abstract

We generalize the concept of triply-degenerate nodal points to non-collinear antiferromagnets. Here, we introduce this concept to insulating quantum antiferromagnets on the decorated honeycomb lattice, with spin-$1$ bosonic quasiparticle excitations known as magnons. We demonstrate the existence of magnonic surface states with constant energy contours that form pairs of magnonic arcs connecting the surface projection of the magnonic triple nodal points. The quasiparticle excitations near the triple nodal points represent three-component bosons beyond that of magnonic Dirac, Weyl, and nodal-line cases. They can be regarded as a direct reflection of the intrinsic spin carried by magnons. Furthermore, we show that the magnonic triple nodal points can split into magnonic Weyl points, as the system transits from a non-collinear spin structure to a noncoplanar one with a nonzero scalar spin chirality. Our results not only apply to insulating antiferromagnets, but also provide a platform to seek for triple nodal points in metallic antiferromagnets.

6 pages, 5 figures + Supplemental Material. To appear in EPL (Europhys. Lett.)

References in corpus (10)

• Double-Weyl phonons in transition-metal monosilicides
• Spin waves in the Frustrated Kagome Lattice Antiferromagnet KFe3(OH)6(SO4)2
• Tunable magnon Weyl points in ferromagnetic pyrochlores
• Absence of magnetic order for the spin-half Heisenberg antiferromagnet on the star lattice
• Chiral anomaly of Weyl magnons in stacked honeycomb ferromagnets
• Emergent pseudospin-1 Maxwell fermions with a threefold degeneracy in optical lattices
• From Type-II Triply Degenerate Nodal Points and Three-Band Nodal Rings to Type-II Dirac Points in Centrosymmetric Zirconium Oxide
• Magnon nodal-line semimetals and drumhead surface states in anisotropic pyrochlore ferromagnets
• Coexistence of New Fermions in Topological Semimetal TaS
• Magnon Hall Effect without Dzyaloshinskii-Moriya Interaction

Cited by in corpus (9)

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• Impurity-induced triple point fermions in twisted bilayer graphene
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• Weyl-triplons in SrCu2(BO3)2
• Topological Weyl magnons and thermal Hall effect in layered honeycomb ferromagnets
• Nonreciprocal superposition state in antiferromagnetic optospintronics
• Two-dimensional Dirac nodal loop magnons in collinear antiferromagnets
• Topological transitions of spin-excitations in insulating chiral antiferromagnets