Discrete modulational instability and bright localized spin wave modes in easy-axis weak ferromagnetic spin chains involving the next-nearest-neighbor coupling  

作　　者：Jiayu Xie Zhihao Deng Xia Chang Bing Tang 谢家玉;邓志豪;昌霞;唐炳(College of Physics, Mechanical and Electrical Engineering, Jishou University, Jishou 416000, China;The Collaborative Innovation Center of Manganese-Zinc-Vanadium Industrial Technology, Jishou University, Jishou 416000, China)

机构地区：[1]College of Physics, Mechanical and Electrical Engineering, Jishou University, Jishou 416000, China [2]The Collaborative Innovation Center of Manganese-Zinc-Vanadium Industrial Technology, Jishou University, Jishou 416000, China

出　　处：《Chinese Physics B》2019年第7期449-458,共10页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.11604121 and 11875126);the Natural Science Fund Project of Hunan Province,China(Grant No.2017JJ3255);the National College Students’ Innovation Entrepreneurship Training Program,China(Grant No.201810531014);the Scientific Research Fund of Hunan Provincial Education Department,China(Grant No.17B212)

摘　　要：We report a theoretical work on the properties of modulational instability and bright type nonlinear localized modes in one-dimensional easy-axis weak ferromagnetic spin lattices involving next-nearest-neighbor couplings.With a linear stability analysis, we calculate the growth rates of the modulational instability, and plot the instability regions.When the strength of the next-nearest-neighbor coupling is large enough, two new asymmetric modulational instability regions appear near the boundary of the first Brillouin zone.Furthermore, analytical forms of the bright nonlinear localized modes are constructed by means of a quasi-discreteness approach.The influence of the next-nearest-neighbor coupling on the Brillouin zone center mode and boundary mode are discussed.In particular, we discover a reversal phenomenon of the propagation direction of the Brillouin zone boundary mode.We report a theoretical work on the properties of modulational instability and bright type nonlinear localized modes in one-dimensional easy-axis weak ferromagnetic spin lattices involving next-nearest-neighbor couplings.With a linear stability analysis, we calculate the growth rates of the modulational instability, and plot the instability regions.When the strength of the next-nearest-neighbor coupling is large enough, two new asymmetric modulational instability regions appear near the boundary of the first Brillouin zone.Furthermore, analytical forms of the bright nonlinear localized modes are constructed by means of a quasi-discreteness approach.The influence of the next-nearest-neighbor coupling on the Brillouin zone center mode and boundary mode are discussed.In particular, we discover a reversal phenomenon of the propagation direction of the Brillouin zone boundary mode.

关 键 词：modulational instability analysis intrinsic LOCALIZED SPIN-WAVE MODES weak FERROMAGNETS NEXT-NEAREST-NEIGHBOR couplings 

分 类 号：O4[理学—物理]