最近邻作用项对一维分子链孤子激发的影响  

Effect on Soliton Excitation in One-Dimensional Molecular-Crystal Chain with the Nearest-Neighboring Interaction

作　　者：王洪丽[1] 陈浩[1] 王瑞强[1] 

机构地区：[1]华南师范大学物理与电信工程学院,广州510006

出　　处：《华南师范大学学报（自然科学版）》2015年第3期34-38,共5页Journal of South China Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(11174088)

摘　　要：在电-声相互作用的一维分子晶体中,电子不仅与在位格点上的声子有相互的作用,同时与近邻格点也存在着微弱的相互作用.为了更真实地求解出一维分子晶体系统的基态问题,以量子化Holstein模型为基础并考虑电子与最近邻格点上声子的相互作用项对其的修正,此时系统处于基态时的Hamiltonian量也发生了相应的改变.运用压缩-相干态展开法和能量极小值等原理,求解出处于基态时极化子系统所满足的非线性Schrdinger方程和对应的孤子解、基态能量.并讨论了最近邻作用项的强度对一维分子链孤子激发如孤子的波峰、波宽、稳定性和系统基态能量的影响.The electron-phonon coupling consists of the on-site electron-phonon interaction and the neighboring inter-site one as the electron should interact with its neighboring local phonons in the one-dimensional molecular-crystal model. In order to give more accurate solution, the effect of the nearest-neighboring interaction based on the quantized Holstein model is studied. Correspondingly, the Hamiltonian of the ground state is modified and then soliton excitation is improved too. By using the squeezed-coherent state expansion method and the energy minimum principle, the nonlinear Schrodinger equation for the one-dimensional molecular-crystal model is proposed, and then the solution and the ground state energy are obtained. Compared with the consequence neglecting the nearest- neighboring interaction, the solution of the nonlinear Schrodinger equation changes and the ground state energy of the polaron are more negative with the augmentation of the nearest-neighboring interaction.

关 键 词：Holstein模型 极化子 压缩-相干态展开法 孤子激发 

分 类 号：O481.1[理学—固体物理]