Meron configurations in easy-plane chiral magnets

Abstract: We demonstrate the existence and study in detail the features of chiral bimerons which are static solutions in an easy-plane magnet with the Dzyaloshinskii-Moriya (DM) interaction. These are skyrmionic textures with an integer topological charge and they present essential analogies to the meron configurations introduced in the context of quark confinement in the O(3) nonlinear sigma-model. We employ a Moebius transformation to show that, for weak chirality, bimeron configurations approach Belavin-Polyakov (BP) solutions characterized by tightly bound vortex and antivortex parts of the same size. Stronger chirality induces different vortex and antivortex sizes and also a detachment of merons, suggesting the possibility for a topological phase transition. Exploiting the fact that bimerons of opposite topological charges may exist in the same material, we demonstrate numerically a mechanism to generate meron pairs.