随杂质位置的变化异质结中的束缚极化子的性质  

Properties of the Polaron in the Heterostructure with the Change of Impurity's Position

作　　者：刘佳[1] 肖景林[1] 

机构地区：[1]内蒙古民族大学物理与机电学院,内蒙古通辽028043

出　　处：《内蒙古民族大学学报（自然科学版）》2006年第3期260-263,共4页Journal of Inner Mongolia Minzu University：Natural Sciences

基　　金：国家自然科学基金资助项目(10347004)

摘　　要：本文对GαAs/AlxGα1-xAs异质结,采用三角势近似异质结势,考虑外界恒定电场以及体纵光学声子和两支界面光学声子的影响,应用改进的LLP中间耦合方法处理电子-声子相互作用和杂质-声子相互作用,计算了极化子结合能随电场强度、杂质位置和电子面密度的变化关系.结果表明:结合能随电场的增强而缓慢增大.IO声子对结合能的负贡献受电子面密度的影响显著增加,LO声子的负贡献相对IO声子贡献较小.另外,三角势的选取说明,导带弯曲引起的势垒变化不容忽视.还须指出的是,电子像势对结合能的影响很小,可以忽略.In this paper,the binding energy of the ground state of a bound polaron near the interface of a polar - polar semiconductor heterojunction is investigated by using the Lee- Low- Pines intermediate coupling method. The influence of a triangular potential approximation of the interface, the electron - phonon and impurity - phonon interactions as well as the half - space bulk longitudinal and interface- optical phonon modes are taken into account. We have performed numerical calculations on the GaAs/AlxGa1 - xAs heterojunction system and studied the relations between the ground state binding energy of the polaron and the impurity position. It is found that the trend of the binding energy is the same as the result without a electric field as a function of impurity position. When the electron area density is increased, the contribution of the interface- optical（IO） modes are greater than that of the bulk longitudinal optical（LO） mode. It is also proved that the conductive band bending should not be neglected. Furthermore, it should be point out that the influence of the electron image potential is negligibly small so that it can be neglected in the future discussion.

关 键 词：半导体异质结 极化子 结合能 三角势近似 电子面密度 

分 类 号：O469[理学—凝聚态物理]