1. Key Laboratory for Optical and Magnetic ResonanceSpectroscopy and Department of Physics, East China Normal University,Shanghai 200062, China;2. Physics Group, Zhuzhou Institute of Technology, Zhuzhou412008, Hunan Province, China
Abstract:
The dynamics of coupled band gap solitons in one-dimensionalHeisenberg ferromagnetic chains with bond alternation is considered analytically. Using the method of multiple scales the nonlinear coupled-mode equations (i.e. Manakov equations) for the upper cutoff mode of acoustic band and the lower cutoff mode of optical band are derived under the quasi-discreteness approximation. Due to the cross-phase modulation the type of soliton excitations may be changed and the vibrating frequencies of these soliton excitations may locate within or outside the gap of magnon frequency bands.