交变电场驱动下耦合双量子点中激子的动力学行为  

Dynamic behaviours of an exciton confined in coupled quantum dots driven by an alternating current electrical field

作　　者：刘承师[1] 马本堃[1] 王立民[1] 

机构地区：[1]北京师范大学物理系,北京100875

出　　处：《物理学报》2003年第8期2020-2026,共7页Acta Physica Sinica

基　　金：教育部博士点基金 (批准号 :960 0 2 70 3 )资助的课题 .~~

摘　　要：利用两点Hubbard模型和Floquet定理 ,研究了交变电场驱动下耦合双量子点中激子的动力学行为 .计算结果表明 ,系统准能级随交变电场振幅的变化出现一系列严格交叉和回避交叉 .在最低的两个准能级的第一个严格交叉点处 ,初始局域状态一般能够保持 ,并且随着点内的电子空穴之间库仑相互作用的增强 ,动态局域化的程度会提高 .在最低的两个准能级的第二和第三个严格交叉点处 ,随着交变电场的增强 ,这种动态局域化被破坏 .在偏离准能严格交叉点和回避交叉点 ,则不能存在动态局域化现象 .With a two-site Hubbard model and Floquet theorem, we investigate the dynamic behaviour of an exciton confined in a coupled double-quantum-dot system driven by an alternating current(AC) electrical field. The calculation shows that the quasi-energy levels versus the amplitude of the external field undergo a series of exact-crossing and avoid-crossing. Generally, the initially localized state can remain forever at the first exact-crossing point of two ground quasi-energy levels. Increasing the interaction of the electron and hole, the degree of dynamical localization is enhanced. At the second exact-crossing point of ground quasi-energy levels, this kind of dynamical localization is decayed. At the point of avoid-crossing and offset from the exact-crossing, the dynamical localization ceases to maintain. This demonstrates the possibility to control the exciton states on extremely short time scales using the appropriate AC field with the adjustable amplitude and frequency, which may be useful for quantum information processing.

关 键 词：交变电场驱动 耦合双量子点 激子 动力学 准能级 动态局域化 Floquet态 电子 空穴 半导体 

分 类 号：O413.1[理学—理论物理]