Confinement of Skyrmion states in noncentrosymmetric magnets

Skyrmionic states in noncentrosymmetric magnets with Lifshitz invariants are investigated within the phenomenological Dzyaloshinskii model. The interaction between the chiral Skyrmions, being repulsive in a broad temperature range, changes into attraction at high temperatures. This leads to a remarkable confinement effect: near the ordering temperature Skyrmions exist only as bound states, and Skyrmion lattices are formed by an unusual instability-type nucleation transition. Numerical investigations on two-dimensional models demonstrate the confinement and the occurrence of different Skyrmion lattice precursor states near the ordering transition that can become thermodynamically stable by anisotropy or longitudinal softness in cubic helimagnets.