Figure 4

Duplication and merging of skyrmion.

The top panels show the snapshots of the magnetization configuration at eight selected times corresponding to the vertical lines in the middle and bottom panels; the middle panels show the time evolution of the average spin components m_x, m_y, m_z; the bottom panels show the time evolution of the skyrmion number Q_s. (a), Duplication of a skyrmion: the D is 3.5 mJ m⁻²; the initial background magnetization of the sample points +z; a current density of 5 × 10¹² A m⁻² (the value is of the input side) is applied along −x direction for 0 ns < t < 0.49 ns followed by a relaxation without applying any current until t = 1 ns. (b), Merging of two skyrmions: the D is 3.5 mJ m⁻²; the initial background magnetization of the sample points +z; a current density of 4 × 10¹² A m⁻² (the value is of the output side) is applied along −x direction for 0 ns < t < 0.64 ns followed by a relaxation until t = 1 ns.