Fig. 2: Emergent electrodynamics of the SkL motion driven by DC current.

a Magnetic field dependence of the differential Hall resistivity \({\rm{Re}}[{\rho }_{yx}^{{\rm{diff}}}]\) for various DC current bias J_DC. The dashed lines denote a spline fit to the regions outside of the SkL phase (see Supplementary Note 2). b Change in the topological Hall resistivity \(\Delta {\rm{Re}}[{\rho }_{yx}^{{\rm{THE}},{\rm{diff}}}]={\rm{Re}}[{\rho }_{yx}^{{\rm{THE}},{\rm{diff}}}]({J}_{{\rm{DC}}})\) −  \({\rm{Re}}[{\rho }_{yx}^{{\rm{THE}},{\rm{diff}}}]({J}_{{\rm{DC}}}=0\,{{\rm{A\; m}}}^{-2})\) in the SkL phase at 0.24 T. c\(\Delta {\rm{Re}}[{\rho }_{yx}^{{\rm{THE}},{\rm{diff}}}]\) converted into skyrmion velocity v_Sk using Eq. (2). We plot a red line as a guide to the eye. The dashed line corresponds to 0.75v_e (see also ‘Methods’ and Supplementary Note 3). The dotted lines in (b) and (c) indicate the crossover points of pinned-creep and creep-flow, with errors indicated in the top subplot of b. For the procedure of error estimation, see ‘Methods’. These measurements were performed by locking into a small oscillation of J_AC = 1.74 × 10⁷ A m⁻² at a frequency of f = 509 Hz, modulated on a DC bias, J_DC. Error bars in (b) and (c) correspond to the standard deviation of the signal estimated in the field polarised regime. Where not visible, error bars are smaller than the data points.