Interaction induced topological magnon in electron-magnon coupled systems

Kosuke Fujiwara; Takahiro Morimoto

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arXiv · 2601.22566

Interaction induced topological magnon in electron-magnon coupled systems

Kosuke Fujiwara·Takahiro Morimoto

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Abstract

We theoretically study the emergence of topological magnons in electron-magnon coupled systems. The magnon dispersion in a ferromagnet usually possesses an effective time reversal symmetry in the absence of Dzyaloshinskii-Moriya (DM) interaction, preventing the appearance of topological magnons. When a spin system is coupled to itinerant electrons, we find that the magnon band structure of the spin system experiences time-reversal symmetry breaking with the electron-magnon interaction via the exchange coupling, where topological magnons arise without requiring strong DM. Specifically, we consider a heterostructure consisting of a ferromagnetic insulator and a transition metal dichalcogenide (TMD) monolayer and investigate topological gap opening in magnon bands. Our findings reveal that even trivial ferromagnets can host topological magnons via coupling to itinerant electronic systems.

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Kosuke Fujiwara, Takahiro Morimoto. 2026-01-30. Interaction induced topological magnon in electron-magnon coupled systems. https://arxiv.org/abs/2601.22566

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