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.
Received: 04 January 2009
Revised: 20 May 2009
Accepted manuscript online:
PACS:
63.20.D-
(Phonon states and bands, normal modes, and phonon dispersion)
Fund: Project supported by the National
Natural Science Foundation of China (Grant No 10574011), and the
Foundation for Researching Group by Beijing Normal University.
Cite this article:
ü Bin-Bin(吕彬彬) and Tian Qiang(田强) Discrete gap breathers in a two-dimensional diatomic face-centered square lattice 2009 Chin. Phys. B 18 4393
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