TY - JOUR
T1 - Instantons in chiral magnets
AU - Hongo, Masaru
AU - Fujimori, Toshiaki
AU - Misumi, Tatsuhiro
AU - Nitta, Muneto
AU - Sakai, Norisuke
N1 - Funding Information:
This work is supported by the MEXT-Supported Program for the Strategic Research Foundation at Private Universities “Topological Science” (Grant No. S1511006) and by the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research (KAKENHI), Grant No. 18H01217. The authors are also supported in part by JSPS KAKENHI Grants No. 18K03627 (T.F.), No. 19K03817 (T.M.), and No. 16H03984 (M.N.). M.H. was also supported by the US Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-FG0201ER41195, and by the RIKEN iTHEMS Program (in particular, the iTHEMS STAMP working group). The work of M.N. is also supported in part by a Grant-in-Aid for Scientific Research on Innovative Areas “Topological Materials Science” (KAKENHI Grant No. 15H05855) from MEXT.
Publisher Copyright:
© 2020 American Physical Society.
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.
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U2 - 10.1103/PhysRevB.101.104417
DO - 10.1103/PhysRevB.101.104417
M3 - Article
AN - SCOPUS:85083335702
SN - 2469-9950
VL - 101
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
IS - 10
M1 - 104417
ER -