Classification of chiral domain-wall dynamics through symmetry analysis

We report the discovery of a previously unreported type of chiral domain-wall (DW) dynamics and establish a symmetry-based framework for classifying the observed types of chiral DW dynamics. In this newly identified type, the symmetric component of the DW speed exhibits a concave-down curvature, in sharp contrast to the conventional concave-up response associated with the equilibrium DW-energy contribution. Sample-specific micromagnetic calculations reproduce only the conventional response and fail to account for this reversed curvature, indicating an additional even contribution beyond the conventional equilibrium DW-energy picture. By incorporating this new response, we show that the chiral DW dynamics observed to date can be classified into three distinct types, all of which are quantitatively described by symmetric and antisymmetric components having the same respective functional forms. This classification provides a systematic framework for investigating diverse chiral DW dynamics and their underlying physics.