晶格振动对激子运动的影响

在本文中用Haga研究极化子时提出的微扰法讨论晶格振动对激子运动的影响。把作者过去的工作推广到电子和空穴质量不相等的普遍情形。在忽略反冲效应中不同波矢的声子之间的相互作用时,导出了激子的基态能量、有效质量、约化质量和内部势能。指出:激子的有效质量和电子、空穴与声子的相互作用有关;激子的约化质量不仅和电子、空穴与声子的相互作用有关,而且还和电子空穴质量比有关;激子形成自陷态的条件并非由电子、空穴与声子相互作用的大小,而是由电子、空穴质量比决定。形成激子自陷的条件是电子、空穴质量比0.261<μ_e/μ_h<3.83。在μ_e/μ_h<0.261或μ_e/μ_h>3.83的情形,激子极化晶体中并不形成自陷态。 关键词：

THE EFFECT OF THE LATTICE VIBRATION ON THE EXCITON MOTION

In this paper, the effect of the lattice vibration on the exeiton motion is discussed by a perturbation method that was developed to investigate the problem of plarons by Haga. Our previous work is generalized to the case that the electron mass and the hole mass are not equal. When we neglect the interaction between phonons of different wave vector in the recoil process, the ground state energy, effeetive mass, reduced mass and inner potential energy are derived. It is shown that the effective mass of the exeiton depends on the interaction between the electron, hole and the phonons reduced mass of the exciton not only depends on the interaction between the electron. Hole and the phonons, but also on the electron and hole mass ratio; the formation of a self trapping exciton is not determined by the magnitude of the interaction between the electron, hole and the phnon, but by the electron and hole mass ratio. A exciton is self trapping when the electron and hole mass ratio is in the range 0.261 <μ_e/μ_h<3.83.