Atomistic Simulations of Antiferromagnetic Solitons and their High-Speed Dynamics

Abstract

In antiferromagnetic materials, localized self-sustaining states called solitons namely Domain Walls and Skyrmions, can be efficiently driven by currents and achieve velocities of several kilometers per second. These solitons are massive particles and therefore cannot travel faster than a limiting velocity akin to the speed of light for the material. The specifics of these high velocity dynamics, in which solitons begin to display relativistic effects, have been well understood for the case of singledimensional particles - domain walls. Here. we perform an extensive and systematic atomistic study of both 1D and 2D soliton dynamics in chiral magnetic materials, both at and away from angular momentum compensation. We present a novel outlook on the role of skyrmion compactness in their deformation patterns, velocity limits, as well as the absence of behaviors similar to ones observed in relativistic DWs. We claim that limits on skyrmion compactness also impede their ability to reach the velocity regime where relativistic effects begin to occur in rapidly moving DWs, due to the critical skyrmion breakdown behavior. These results could prove to be significant to the field of spintronics, as well as the potential applications of skyrmions for novel logic and memory devices.