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

• 来源期刊: 中国物理B（英文版）
• 关键词: discrete gap breathers two-dimensional diatomic face-centered square lattice linearstability coupling parameters
• 年，卷（期）: 2009,（10）
• 页码范围: 4393-4406
• 页数: 14页
• 语种: 英文

摘要

In this paper we study the existence and stability of two-dimensional discrete gap breathers in a two-dimensionaldiatomic face-centered square lattice consisting of alternating light and heavy atoms,with on-site potential and couplingpotential.This study is focused on two-dimensional breathers with their frequency in the gap that separates the acousticand optical bands of the phonon spectrum.We demonstrate the possibility of the existence of two-dimensional gapbreathers by using a numerical method.Six types of two-dimeusional 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 differencebetween one-dimensional discrete gap breathers and two-dimensional discrete gap breathers is also discussed.We ttseAubry's theory to analyze the stability of discrete gap breathers in the two-dimensional diatomic face-centered squarelattice.