声子之间相互作用对量子点中极化子性质的影响  

Influence of Interaction between Phonons on Properties of Polaron in a Quantum dot

作　　者：张鹏[1] 肖景林[2] 

机构地区：[1]中国石油大学(北京)数理系,北京102249 [2]内蒙古民族大学物理与机电学院,内蒙古通辽028043

出　　处：《发光学报》2007年第1期35-38,共4页Chinese Journal of Luminescence

基　　金：国家自然科学基金(10347004);中国石油大学校长基金(2005)资助项目

摘　　要：研究了抛物量子点中弱耦合极化子的性质。采用线性组合算符和微扰法,导出了抛物量子点中极化子的基态能量。当计及电子在反冲效应中发射和吸收不同波矢的声子之间的相互作用时,讨论了对量子点中极化子的基态能量的影响。通过数值计算,结果表明,量子点中极化子基态能量随量子点的有效受限长度的减小而迅速增大,随电子-LO声子的耦合强度的增加而减少。当l0>1.4时,声子之间的相互作用不能忽略。Recently, with the quick development of nanofabrication technology to material, the physical characteristics of low dimensional material have aroused great interest. The electron energy spectrum of such quantum dot is fully quantized. Such systems are of great interest in fundamental studies, as well as in practical application for microelectronic devices. Electron-phonon interaction, which plays an important role in electronic and optical properties of polar crystalline materials in three dimensions, will have pronounced effects in lowdimensional systems as well. The properties of polaron in quantum dot have been studied by many theoretical and experiment methods. Zhu and Gu studied the ground state and self-energy of the weak-coupling polaron in a quantum dot by using the second order Rayleigh-Schsrdinger perturbation theory. Using the Fock approximation of Matz and Burkey, Lepine and Bruneau discussed the effect of an anisotropic confinement on the ground state energy of a polaron in a parabolic quantum dot. Mukhopadhyay and Chatterjee investigated the polaronic corrections to the first excited state energy of an electron in a parabolic quantum dot using a canonical transformation method based on the L. L. P. G formation. Li and Zhu investigated the strong coupling polaron in a parabolic quantum dot by the Landan-Pekar variational treatment. It is shown that both the polaron binding energy and the average number of virtual phonons around the electron decrease with increasing the effective confinement length. The results indicate that the polaronic effects are more pronounced in quantum dots than those in two-dimensional and three-dimensional cases. With the use of variational approach, the effects of the bulk-LO phonon on the impurity binding energy in a GaAs quantum dot are studied by Es-sbai et ai. Upon using a curvilinear coordinates system, Cantele et ai. calculated the effective mass for a particle confined in an ellipsoidal quantum dot. Xie proposed a procedure to calculate the polaron effect of Dcenters

关 键 词：抛物量子点 极化子 声子间相互作用 基态能量 

分 类 号：O469[理学—凝聚态物理] O472.3[理学—电子物理学]