摘要
采用线性组合算符和幺正变换方法研究了磁场和库仑场对抛物量子点中极化子激发态性质的影响。导出了抛物量子点中弱耦合束缚磁极化子的振动频率、第一内部激发态能量、激发能量与量子点的有效受限长度、库仑束缚势和磁场的回旋频率之间的变化关系。通过数值计算,结果表明:抛物量子点中弱耦合束缚极化子的振动频率、第一内部激发态能量、激发能量均随量子点的有效受限长度减小而迅速增大。随库仑束缚势增大而增大。随磁场的回旋频率的增加而增大。
With the development of several experimental techniques vapour deposition, molecular beam epitaxy and electron beam lithograph , for example, metalorgnic chemical y combined with reverse mesa etching, there has been of considerable interest in understanding of hydrogenic-impurity states in low-dimensional semi- conductor heterostructures such as quantum wells, quantum wires, and quantum dots. In recent years, there is of great interest in investigating quantum dots both theoretically and experimentally. Due to the small structures of QDs, some physical properties such as optical and electron transport characteristic are quite different from those of the bulk materials. The study on the impurity states in these low dimensional structures is an important aspect on which many theoretical and experimental works based.Recently there has been a considerable number of theoretical studies on the effect of a bound magnetopo- laron in a parabolic quantum dot. However, there has very few article on the properties of the internal excited state of bound magnetopolaron by using the linear combination operator in parabolic quantum dot up to date. In this paper, by using the linear combination operator and the unitary transformation method, the proper- ties of the excited state of the weak-coupling bound magnetopolaron in a parabolic quantum dot were calculated. The relation of the vibrational frequency, the first internal excited state energy, the excitation energy and the resonance frequency of the weak-coupling bound magnetopolaron with the effective confinement length of the quantum dot, the Coulomb bound potential, the electron-LO-phonon coupling strength and the cyclotron fre- quency in a parabolic quantum dot were obtained. Results show that he vibrational frequency, the first internal- excited state energy, the excitation energy and the resonance frequency of the bound magnetopolaron increase rapidly with decreasing the effective confinement length in the electron-phonon weak-coupling case in a para- bolic quantum dot. They also increase with increasing the Coulomb bound potential and decreasing the elec- tron-phonon coupling strength
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第6期832-836,共5页
Chinese Journal of Luminescence
基金
国家自然科学基金资助项目(10347004)
关键词
抛物量子点
束缚磁极化子
受限长度
第一内部激发态能量
parabolic quantum dot
weak-coupling bound magnetopolaron
effective confinement length
thefirst internal excited state energy
