量子点中双极化子和磁双极化子的研究进展

综述了近年来对抛物线性限制势量子点中强耦合双极化子和磁双极化子的部分研究工作.从抛物量子点中2个电子-声子体系的哈密顿量出发,采用Lee-Low-Pines-Huybrechts变分方法,研究了量子点中强耦合双极化子的振动频率、诱生势和有效势随电子-声子耦合强度、两电子相对距离和量子点半径的变化规律;采用Tokuda改进的线性组合算符法研究了温度和LO声子效应对强耦合双极化子的有效质量和平均声子数的影响.基于Lee-Low-Pines幺正变换,采用Pekar类型变分法研究了抛物量子点中强耦合磁双极化子的内部激发态性质,当考虑自旋和外磁场影响时,研究了二维量子点中强耦合磁双极化子基态的能量、声子平均数以及第一激发态的能量、声子平均数随量子点受限强度、介电常数比、电子-声子耦合强度和磁场的回旋共振频率的变化规律.

Research Progress of the Bipolaron and the Magneto-bipolaron in a Parabolic Quantum

This article is a review on our studies in recent years on the research progress of the bipolaron and the magneto-bipolaron in a parabolic quantum dot. Based on a Hamiltonian of the two electrons-longitudinal optical phonon system, the vibration frequency and the effective potential of the strong coupling bipolarons with the strength of the electron-phonon coupling and the relative distance between the electrons and the quantum dot＇ s radius are derived using the Lee-Low-Pines-Huybrechts variational method. The influence of the temper- ature and the LO phonons on the average number of phonon and the effective mass of the strong-coupling bipol- aron in a parabolic quantum dot have been investigated using the Tokuda modified linear-combination operator method. The properties of the internal excited state of the strong coupling magneto-bipolarons in a parabolic quantum dot are studied using the variation method of Pekar type based on the Lee-Low-Pines＇ unitary trans- formation. Considering the influence of the electronic spin and the external magnetic field, the ground state energy, the average number of phonon, the first excited state energy and the average number of phonon of the magneto-bipolarons with the confinement strength, the dielectric constant ratio, the electron-phonon coupling and the cyclotron frequency are derived in two-dimensional quantum dot.