TY - JOUR
T1 - Instantons in chiral magnets
AU - Hongo, Masaru
AU - Fujimori, Toshiaki
AU - Misumi, Tatsuhiro
AU - Nitta, Muneto
AU - Sakai, Norisuke
PY - 2020/3/1
Y1 - 2020/3/1
N2 - 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 the Dzyaloshinskii-Moriya (DM) interaction. By introducing an easy-Axis potential and a staggered magnetic field, we obtain a phase diagram consisting of ground-state phases with two points (or one point) in the easy-Axis dominant cases, a helical modulation at a fixed latitude of the sphere, and a tricritical point allowing helical modulations at an arbitrary latitude. We find that instantons (or skyrmions in two-dimensional Euclidean space) appear as composite solitons in different fashions in these phases: Temporal domain walls or wall-Antiwall pairs (bions) in the easy-Axis dominant cases, dislocations (or phase slips called merons) with fractional instanton numbers in the helical state, and isolated instantons and calorons living on the top of the helical modulation at the tricritical point. We also show that the models with DM interaction and an easy-plane potential can be mapped into those without them, providing a useful tool to investigate the model with the DM interaction.
AB - 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 the Dzyaloshinskii-Moriya (DM) interaction. By introducing an easy-Axis potential and a staggered magnetic field, we obtain a phase diagram consisting of ground-state phases with two points (or one point) in the easy-Axis dominant cases, a helical modulation at a fixed latitude of the sphere, and a tricritical point allowing helical modulations at an arbitrary latitude. We find that instantons (or skyrmions in two-dimensional Euclidean space) appear as composite solitons in different fashions in these phases: Temporal domain walls or wall-Antiwall pairs (bions) in the easy-Axis dominant cases, dislocations (or phase slips called merons) with fractional instanton numbers in the helical state, and isolated instantons and calorons living on the top of the helical modulation at the tricritical point. We also show that the models with DM interaction and an easy-plane potential can be mapped into those without them, providing a useful tool to investigate the model with the DM interaction.
UR - http://www.scopus.com/inward/record.url?scp=85083335702&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85083335702&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.101.104417
DO - 10.1103/PhysRevB.101.104417
M3 - Article
AN - SCOPUS:85083335702
VL - 101
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 2469-9950
IS - 10
M1 - 104417
ER -