Modulational instability, quantum breathers and two-breathers in a frustrated ferromagnetic spin lattice under an external magnetic field

• 来源期刊: 中国物理B（英文版）
• 关键词: quantum breathers quantum two-breathers modulational instability frustrated ferromagnetic chains
• 年，卷（期）: 2018,（9）
• 页码范围: 641-651
• 页数: 11页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/9/097501

摘要

The modulational instability,quantum breathers and two-breathers in a frustrated easy-axis ferromagnetic zig-zag chain under an external magnetic field are investigated within the Hartree approximation.By means of a linear stability analysis,we analytically study the discrete modulational instability and analyze the effect of the frustration strength on the discrete modulational instability region.Using the results from the discrete modulational instability analysis,the presence conditions of those stationary bright type localized solutions are presented.On the other hand,we obtain the analytical expressions for the stationary bright localized solutions and analyze the effect of the frustration on their emergence con-ditions.By taking advantage of these bright type single-magnon bound wave functions obtained,quantum breather states in the present frustrated ferromagnetic zig-zag lattice are constructed.What is more,the analytical forms for quantum two-breather states are also obtained.In particular,the energy level formulas of quantum breathers and two-breathers are derived.