中国物理B ›› 2009, Vol. 18 ›› Issue (10): 4393-4406.doi: 10.1088/1674-1056/18/10/049

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Discrete gap breathers in a two-dimensional diatomic face-centered square lattice

吕彬彬, 田强   

  1. Department of Physics, Beijing Normal University, Beijing 100875, China
  • 收稿日期:2009-01-04 修回日期:2009-05-20 出版日期:2009-10-20 发布日期:2009-10-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10574011), and the Foundation for Researching Group by Beijing Normal University.

Discrete gap breathers in a two-dimensional diatomic face-centered square lattice

ü Bin-Bin(吕彬彬)† and Tian Qiang(田强)   

  1. Department of Physics, Beijing Normal University, Beijing 100875, China
  • Received:2009-01-04 Revised:2009-05-20 Online:2009-10-20 Published:2009-10-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10574011), and the Foundation for Researching Group by Beijing Normal University.

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摘要： In this paper we study the existence and stability of two-dimensional discrete gap breathers in a two-dimensional diatomic face-centered square lattice consisting of alternating light and heavy atoms, with on-site potential and coupling potential. This study is focused on two-dimensional breathers with their frequency in the gap that separates the acoustic and optical bands of the phonon spectrum. We demonstrate the possibility of the existence of two-dimensional gap breathers by using a numerical method. Six types of two-dimensional gap breathers are obtained, i.e., symmetric, mirror-symmetric and asymmetric, whether the center of the breather is on a light or a heavy atom. The difference between one-dimensional discrete gap breathers and two-dimensional discrete gap breathers is also discussed. We use Aubry's theory to analyze the stability of discrete gap breathers in the two-dimensional diatomic face-centered square lattice.

Abstract: In this paper we study the existence and stability of two-dimensional discrete gap breathers in a two-dimensional diatomic face-centered square lattice consisting of alternating light and heavy atoms, with on-site potential and coupling potential. This study is focused on two-dimensional breathers with their frequency in the gap that separates the acoustic and optical bands of the phonon spectrum. We demonstrate the possibility of the existence of two-dimensional gap breathers by using a numerical method. Six types of two-dimensional gap breathers are obtained, i.e., symmetric, mirror-symmetric and asymmetric, whether the center of the breather is on a light or a heavy atom. The difference between one-dimensional discrete gap breathers and two-dimensional discrete gap breathers is also discussed. We use Aubry's theory to analyze the stability of discrete gap breathers in the two-dimensional diatomic face-centered square lattice.

Key words: discrete gap breathers, two-dimensional diatomic face-centered square lattice, linear stability, coupling parameters

中图分类号:  (Phonon states and bands, normal modes, and phonon dispersion)

  • 63.20.D-
61.50.Ah (Theory of crystal structure, crystal symmetry; calculations and modeling) 63.20.Pw (Localized modes) 71.15.-m (Methods of electronic structure calculations)