由高斯型波函数计算GaAs量子点中电子—空穴与声学声子的耦合特性  

On the Computation of Coupling Characteristics between Electron-hole and Acoustic Phonons in GaAs Quantum Dots Based on Gaussian Wavefunctions

作　　者：张明亮[1] 

机构地区：[1]暨南大学电子工程系,广州510632

出　　处：《科学技术与工程》2014年第5期178-182,共5页Science Technology and Engineering

摘　　要：在固态—空腔量子电动力学系统中,研究半导体量子点跟固体环境中声学声子耦合时,通常忽略压电耦合,仅考虑形变势耦合。针对GaAs量子点的不同尺寸(12 nm或24 nm),由高斯型波函数出发并考虑电子和空穴局域化长度差别(δl=l e-l h),计算并给出量子点跟声学声子两种耦合机制对应的声子谱函数,以及声子辅助量子点耦合空腔的散射率。结果发现δl/l e取值变化(0.1或0.2)时,对于小尺寸量子点,压电耦合跟形变势耦合相比都可以忽略;对于大尺寸量子点中,δl/l e取0.2时压电耦合跟形变势耦合相比就变得不能忽略。In solid-state cavity quantum electrodynamics（cQED） systems,semiconductor quantum dots（QDs）interact with bulk phonons in the solid environment besides interacting with the cavity modes.When a QD interacts with acoustic phonons,deformation potential coupling is usually considered much more important than piezoelectric coupling.Based on Gaussian wavefunctions,the coupling matrix elements between electron-hole and acoustic phonons were calculated for two GaAs QDs of different sizes（12 nm or 24 nm）.The difference between electron＇s and hole＇s localized length（δl = l e- l h） has been taken into consideration.Then the feeding rates of acoustic phonons due to two coupling mechanisms were calculated.Changing δl / l e from 0.1 to 0.2,the piezoelectric coupling can be ignored compared with deformation potential coupling for the small size QD.However,the piezoelectric coupling can not be ignored when δl / l e is 0.2 for the big size QD.

关 键 词：量子点 声学声子 压电耦合 形变势耦合 

分 类 号：O471.1[理学—半导体物理]