Spin wave mode coupling in antiskyrmions induced by rotational symmetry breaking

The antiskyrmion, as a topological structure, can be stabilized by anisotropic Dzyaloshinskii-Moriya interaction. We investigated the dynamic properties of antiskyrmions through micromagnetic simulations. The field-dependent evolution of the antiskyrmion expresses a square shape or an elongated shape, due to its spin configuration with the combination of N\'eel-type and Bloch-type walls. This spin configuration with the broken rotational symmetry leads to a notable mode coupling between the breathing mode and the azimuthal spin wave mode under microwave excitation. The same mode coupling can also exist in the skyrmion system with a small in-plane magnetic anisotropy. Our findings emphasize that the rotational symmetry of the spin configuration may play a significant role in the dynamic properties of antiskyrmions and their relevance to magnonics applications.