Discrete modulational instability and bright localized spin wave modes in easy-axis weak ferromagnetic spin chains involving the next-nearest-neighbor coupling
Xie Jiayu1, Deng Zhihao1, Chang Xia1, Tang Bing1, 2, †
       

The product PQ versus the wave number q for different values of γ: (a) without the DM interaction; (b) in the presence of the DM interaction. The used system parameters in the two figures are the same as those in Figs. 1 and 2, respectively.