Instantons in chiral magnets

• DOI: 10.1103/physrevb.101.104417
• Publication Date: 2020-03-23T16:14:22Z
• Authors: Masaru Hongo; Toshiaki Fujimori; Tatsuhiro Misumi; Muneto Nitta; Norisuke Sakai
• Keywords: Instanton; Skyrmion; Sigma model; Tricritical point

We exhaustively construct instanton solutions and elucidate their properties in one-dimensional antiferromagnetic chiral magnets based on the $O(3)$ nonlinear sigma model description of spin chains with Dzyaloshinskii-Moriya (DM) interaction. By introducing an easy-axis potential a staggered magnetic field, we obtain phase diagram consisting ground-state phases two points (or one point) dominant cases, helical modulation at fixed latitude sphere, tricritical point allowing modulations arbitrary latitude. find that instantons skyrmions two-dimensional Euclidean space) appear as composite solitons different fashions these phases: temporal domain walls or wall-antiwall pairs (bions) dislocations slips called merons) fractional numbers state, isolated calorons living top point. also show models DM interaction easy-plane can be mapped into those without them, providing useful tool to investigate