磁场对非对称量子点中束缚磁极化子性质的影响

Influence of Magnetic Field on Properties of Bound Magnetopolaron in an Asymmetric Quantum Dot

采用线性组合算符和幺正变换方法研究磁场对非对称量子点中弱耦合束缚磁极化子性质的影响。导出量子点中弱耦合束缚磁极化子振动频率和基态能量随量子点的横向和纵向有效受限长度、库仑束缚势、磁场的回旋共振频率和电子-声子耦合强度的变化关系。数值计算结果表明:非对称量子点中弱耦合束缚磁极化子的振动频率和基态能量随量子点的横向和纵向有效受限长度的减小而迅速增大。振动频率随库仑束缚势和磁场的回旋共振频率的增加而增大。基态能量随库仑束缚势和电子-声子耦合强度的增加而减小。

Lots of investigator＇s interests, in the problem of a polaron and magnetopolaron bound to a hydrogenic impurity and interacting with the longitudinal optical phonon field in an ionic crystal or a polar semiconductor, have been maintained over years. Due to the small structures of quantum dot some physical properties such as optical and electron transport characteristics are quite different from those of the bulk materials, especially. There has been great interest in investigation quantum dots both theoretically and experimentally. Many investigators studied the properties of the polaron and magnetopolaron in an asymmetry quantum dots in many aspects by a variety of methods. Recently, the properties of weak-coupling magnetopolaron in an asymmetry quantum dots have been studied using the linear combination operator and the unitary transformation methods by the present authors. However, using linear combination operator method, the influence of the Cou- lomb field on the properties of bound polaron and bound magnetopolaron in an asymmetry quantum dots has not been fully investigated so far. The influence of the magnetic field on the properties of weak-coupling bound magnetopolaron in an asymmetry quantum dots are studied. The vibrational frequency and the ground state energy of the weak-coupling bound magnetopolaron in an asymmetry quantum dots are derived by using the linear combination operator and the unitary transformation methods. We obtain the expressions of ground state energy and vibrational frequency for the weak-coupling bound magnetopolaron in an asymmetry quantum dots as a function of the transverse and longitudinal effective confinement length of quantum dot, cyclotron resonance frequency of magnetic felid, Coulomb bound potential and the electron-phonon coupling strength. Numerical calculations are performed and the results show that the vibration frequency and the ground state energy of the weak-coupling bound magnetopolaron in an asymmetries quantum dot will increase strongl effective confinement length of quantum dot. The vibrational y with decreasing the transverse and longitudinal frequency of the weak-coupling bound magnetopo- laron will increase with increasing the cyclotron resonance frequency of magnetic felid and Coulomb bound potential, whereas the ground state energy of bound magnetopolaron will decrease with increasing the Coulomb bound potential and electron-phonon coupling strength