Controlled Separation of Skyrmions and Antiskyrmions by Kitaev Interaction

As topological quasi-particles in magnetic materials, skyrmions and antiskyrmions show potential in spintronics for information storage and computing. However, effectively controlling and separating these entities remain significantly challenging. Here, we demonstrate that anisotropic Kitaev exchange can distinctly influence the static and dynamic behaviors for skyrmions and antiskyrmions, thus aiding their manipulation and separation. Employing the monolayer frustrated magnet NiBr2 as a model system, we construct a magnetic field-strain phase diagram to explore the strain-controlled stability of these topological structures. The introduction of the Kitaev term breaks the energy degeneracy among magnetic structures with various helicities, leading to a translation-rotation mode transition with an increase in current. Importantly, due to their different rotational symmetries, the skyrmion and antiskyrmion show distinct critical behaviors and rotational dynamics, which are governed by the Kitaev parameters. These phenomena enable the design of two proof-of-concept spintronics devices, i.e., a skyrmion separator and a non-gate logic unit.