非对称量子点中磁极化子的声子平均数

Mean Number of Phonons for Manetopolaron in an Asymmetric Quantum Dot

采用线性组合算符方法研究了非对称量子点中强、弱耦合磁极化子的声子平均数的性质。导出了非对称量子点中强、弱耦合磁极化子的声子平均数和振动频率随量子点的横向和纵向受限强度,电子-声子耦合强度的变化关系。对RbCl晶体进行数值计算,结果表明非对称量子点中强、弱耦合磁极化子的声子平均数和振动频率随量子点的横向和纵向受限强度和电子-声子耦合强度的增大而迅速增大。

In the early 1980＇s, Tokuda investigated the mean number of phonons in the cloud around the elec- tron for both the optical and the piezoelectric polarons within the scheme of variational approach based on the unitary transformation and the method of a Lagrange multiplier. The properties of the mean number of phonons of magnetopolaron are investigated by many investigators using many other methods. The properties of the mean number of phonons of the magnetopolaron in a surface of crystals and quantum wire have been studied using the linear-combination operator and unitary transformation method by one of the present authors and co- worker. Recently, the properties of the mean number of phonons of the magnetopolaron and the bound magneto- polaron in a symmetric quantum dot have been investigated using the linear-combination operator and the vari- ational method of Pekar type method by one of the present authors and a co-worker. However, using a linear- combination operator method, the properties of the mean number of phonons for magnetopolaron in an asym- metric quantum dot have not been investigated so far. In this paper, the influences the asymmetric parabolicconfined potential on the properties of the mean number of phonons for the magnetopolaron in quantum dot were studied by using a linear-combination operator and unitary transformation method. The relations between the mean number of phonons and the vibrational frequency of the strong- and weak-coupling magnetopolaron in an asymmetric quantum dot with the transverse and longitudinal direction confinement strength of the quantum dot and the electron-phonon coupling strength are derived. Numerical calculations on the RbC1 crystal, as an example, were performed, and the results show that the mean number of phonons and the vibrational frequency of the strong-coupling polaron will increase strongly with increasing the transverse direction and longitudinal di- rection confinement strength of the quantum dot, and will increase with increasing the electron-phonon coupling strength.