Figure 3.

Vector plots of m_z showing the time progression of the inversion at a field slightly higher than $+|{\mathbf{H}}_{\mathrm{P}}|$ (time indicated in the bottom right-hand corner). (a) The hexagonal state collapses into (b,c) a transient state, which contains antiskyrmions and elliptical skyrmions (marked with AS and ES in c). (d) The antiskyrmions are annihilated at the end of the inversion, and the white dotted hexagon shows the position of a skyrmion before the inversion to indicate the shift of the inverted lattice with respect to the original one. (e) A close-up of an antiskyrmion, marked in the white rectangle in (b). (f) The temporal evolution of the global topological charge Q shows that it vanishes in the transient state due to negatively charged antiskyrmions.