中国物理B ›› 2007, Vol. 16 ›› Issue (1): 228-235.doi: 10.1088/1009-1963/16/1/039

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Discrete gap breathers in a diatomic K2--K3--K4 chain with cubic nonlinearity

李宓善1, 田强2   

  1. (1)Department of Physics, Beijing Jiaotong University, Beijing 100044, China; (2)Department of Physics, Beijing Normal University, Beijing 100875, China
  • 收稿日期:2005-12-23 修回日期:2006-08-17 出版日期:2007-02-01 发布日期:2007-02-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10575074), the Specialized Research Fund for the Doctoral Program of Higher Education of China and the Foundation of Key Laboratory of Thin Films, Jiangsu Province, China.

Discrete gap breathers in a diatomic K2--K3--K4 chain with cubic nonlinearity

Tian Qiang(田强)a)† and Li Mi-Shan(李宓善)b)   

  1. a Department of Physics, Beijing Normal University, Beijing 100875, China; b Department of Physics, Beijing Jiaotong University, Beijing 100044, China
  • Received:2005-12-23 Revised:2006-08-17 Online:2007-02-01 Published:2007-02-01
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10575074), the Specialized Research Fund for the Doctoral Program of Higher Education of China and the Foundation of Key Laboratory of Thin Films, Jiangsu Province, China.

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摘要： The discrete gap breathers (DGBs) in a one-dimensional diatomic chain with K2--K32--K4 potential are analysed. Using the local anharmonicity approximation, the analytical investigation has been implemented. The dependence of the central amplitude of the discrete gap breathers on the breather frequency and the localization parameter are calculated. With increasing breather frequency, the DGB amplitudes decrease. As a function of the localization parameter, the central amplitude exhibits bistability, corresponding to the two branches of the curve \omega = \omega (\zeta). With a nonzero cubic term, the HS mode of DGB profiles becomes weaker. With increasing $K_{3}$, the HS mode of DGB profiles becomes weaker and a bit narrower. For the LS mode, with increasing K3, the central particle amplitude becomes larger, and the DGB profile becomes much sharper. But, as k3 increases further, the central particle amplitude of the LS mode becomes smaller.

关键词: discrete gap breather, diatomic chain, cubic nonlinearity

Abstract: The discrete gap breathers (DGBs) in a one-dimensional diatomic chain with K2--K3--K4 potential are analysed. Using the local anharmonicity approximation, the analytical investigation has been implemented. The dependence of the central amplitude of the discrete gap breathers on the breather frequency and the localization parameter are calculated. With increasing breather frequency, the DGB amplitudes decrease. As a function of the localization parameter, the central amplitude exhibits bistability, corresponding to the two branches of the curve $\omega = \omega (\zeta)$. With a nonzero cubic term, the HS mode of DGB profiles becomes weaker. With increasing $K_{3}$, the HS mode of DGB profiles becomes weaker and a bit narrower. For the LS mode, with increasing K3, the central particle amplitude becomes larger, and the DGB profile becomes much sharper. But, as k3 increases further, the central particle amplitude of the LS mode becomes smaller.

Key words: discrete gap breather, diatomic chain, cubic nonlinearity

中图分类号:  (Localized modes)

  • 63.20.Pw
63.20.Ry (Anharmonic lattice modes)