Description
Two-dimensional (2D) antiferromagnets have attracted intensive interest for next-generation magnonic applications owing to their ultrafast spin dynamics and absence of stray field. However, the microscopic mechanism underlying magnon-magnon coupling in 2D antiferromagnets remains poorly understood and lacks direct experimental verification. Here, we systematically study magnon-magnon coupling in the 2D A-type antiferromagnet CrCl₃ using broadband antiferromagnetic resonance, combined with theoretical analysis and micromagnetic simulations. A clear mode anti-crossing with a frequency gap of 0.2 GHz is observed between acoustic and optical magnon modes. Systematic magnetic field-dependent experiments and theoretical analysis rule out magnetic anisotropy, Dzyaloshinskii-Moriya interaction as dominant factors. Instead, micromagnetic simulations show that non-uniform microwave excitation induced dynamic dipolar interactions are verified to drive the symmetry breaking and realize magnon-magnon coupling in CrCl₃. Our findings prove dynamic dipolar interaction can induce magnon-magnon coupling in 2D antiferromagnets, offering insights for the design of low-power, tunable magnonic devices.
