Anisotropic magnon frequency comb based on antiferromagnetic bimerons

The interaction between propagating magnons and topological spin textures is attracting a lot of recent attention from the magnonic community. It has been shown that the three-wave mixing between magnons and breathing skyrmion can induce the magnon frequency comb (MFC) with equidistant coherent peaks. However, a magnetic bimeron is a nontrivial spin texture and is regarded as the counterpart of the skyrmion in easy-plane magnets with Dzyaloshinskii–Moriya interaction, which allows anisotropic magnon propagations. This raises the question of whether the nonlinear interaction between magnons and bimerons can generate an MFC. If so, how does the direction of magnon propagation affect the characteristics of the MFC? In this Letter, we demonstrate that the three-wave mixing between propagating magnons and locally breathing bimerons can induce a terahertz MFC in easy-plane antiferromagnets. Micromagnetic simulations reveal that the three-wave coupling strength weakly depends on the driving frequency, but it strongly relies on the propagation direction of incident magnons. Our findings uncover the anisotropic nature of MFC in bimeron structures, which may have potential applications for ultrafast magnonic devices with spectroscopy, metrology, and sensing functionalities.