Figure 4: Skyrmion dynamics described by Thiele equation Eq. (5).

The figures (a–d) show the dynamics in the cases (A1), (A2), (B1) and (B2), respectively, using the potential in Fig. 2b,c (see text). The blue dot indicate the skyrmion on layer 1. The red dot represents the skyrmion on layer 2 for the cases (A1) and (A2). The purple dot is also for the skyrmion on layer 2, but in the cases (B1) and (B2). On layer 1, the current j_s,1 = j_s,1e_x is applied to make the skyrmion (blue dot) on layer 1 collide with the other skyrmion (red or purple dot) on layer 2 (see text). The trajectory of the skyrmion on layer 1 is shown by the blue curves. The red and purple curves are the trajectories of the skyrmion on layer 2, respectively.