Lattice structure of baby skyrmions

We study the zero-temperature lattice structure of baby skyrmions using a full-field numerical minimization algorithm. We place baby skyrmions inside different parallelogram unit cells and impose periodic boundary conditions. We find that the minimum energy is obtained for the hexagonal lattice and that the skyrmion splits into quarter-skyrmions in the resulting configuration. In particular, the energy is lower on the hexagonal lattice than on the well-studied rectangular lattice, where splitting into half-skyrmions is observed.