计及次近邻非谐相互作用下原子链中的非线性元激发  

Nonlinear elementary excitations in a monoatomic chain with second nearest neighbour anharmonic interaction

作　　者：冯培成[1] 王登龙[1] 

机构地区：[1]湘潭大学物理系

出　　处：《物理学报》2003年第6期1332-1336,共5页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :5 98710 44和 10 0 0 5 0 0 7);湖南省自然科学基金 (批准号 :0 0JJY2 0 0 7)资助的课题~~

摘　　要：利用多重尺度法 ,研究了谐振、非谐的近邻和次近邻相互作用下单原子链的晶格振动行为 ,发现非传播孤子在单原子链Brillouin区的任何位置均有可能存在 .与仅考虑最近邻相互作用下的单原子链的孤子群速相比 ,此时链中孤子的群速在Brillouin中央增大且衰减得更快 ;在Brillouin区会出现另一个群速为零的位置 .同时 。By using a multiple scales method, we study the lattice vibration of a monoatomic chain taking into account the nearest neighbour and the second next nearest neighbour harmonic and anharmonic interactions. It is shown that nonpropagating solitons exist in any position of the Brillouin zone. Compared with that of a soliton in monoatomic chains with only nearest-neighbour interactions, the group velocity at the centre of the Brillouin zone is enhanced but attenuates more rapidly. In addition, a new position of zero velocity for the soliton is found in the first Brillouin. Our results show that the amplitude of this kind of soliton increases and the location of the soliton with the largest amplitude is close to the centre of the Brillouin zone.

关 键 词：单原子链 非谐次近邻相互作用 非传播孤子 晶格振动 孤子群速 

分 类 号：O562[理学—原子与分子物理]