Ballistic magnon circulators with magnetic skyrmions

Spin waves, quantized as magnons, constitute a fundamental class of excitations and serve as one of the primary angular momentum carriers in magnetic systems. Devoid of Joule heating, a magnonic device that routes spin waves between different ports holds promise for an energy-efficient information infrastructure. Here, we systematically investigate the transport behavior of a magnetic skyrmion-based magnon circulator, a representative device that directs spin wave flow in a non-reciprocal manner. Particularly, a ballistic transport model is established, where the scattering of spin waves by magnetic skyrmions is simplified as magnon deflection by fictitious electromagnetic fields within the skyrmions. Through the combination of ballistic analyses and micromagnetic simulations, the circulation performance is rigorously evaluated for multiple magnon circulators.