非对称量子点中弱耦合束缚极化子的性质

Properties of Weak-coupling Bound Polaron in an Asymmetric Quantum Dot

采用线性组合算符和幺正变换方法研究了非对称量子点中弱耦合束缚极化子的性质。导出了非对称量子点中弱耦合束缚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,库仑束缚势和电子-声子耦合强度的变化关系。通过数值计算,结果表明:非对称量子点中弱耦合束缚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。

In recent years, with the quick development of nanofabrication technology to material, the physical characteristics of low dimensional material have aroused great interest. The lots of novel effects of the quantum dots systems have attracted more and more physicists. Because of the wide device applications and a lot of new optical properties and electron transport characteristics in such structures, understanding the electronic properties of these systems is of particular importance. Many investigators studied the properties of bound polaron in a quantum dot in many aspects by a variety of theoretical and experimental methods. Recently, the properties of polaron in asymmetric quantum dot have been studied by using the linear combination operator and the unitary transformation methods by the present authors. However, using linear combination operator method, the properties of bound polaron in an asymmetries quantum dot has not been investigated so far. In this paper, influences of the transverse and longitudinal effective confinement length of quantum dot, the coulomb bound potential and the electron-phonon coupling strength on the properties of weak-coupling bound polaron in an asymmetries quantum dot were studied. We obtain an expression for the vibration frequency and the ground state energy of the weak-coupling bound polaron in an asymmetries quantum dot as a function of the transverse and longitudinal effective confinement length of quantum dot, the coulomb bound potential and the electron-phonon coupling strength by using a linear combination operator and the unitary transformation method. Numerical calculations were performed and the results show that the vibration frequency and the ground state energy of the weak-coupling bound polaron in an asymmetries quantum dot will strongly increase with decreasing the transverse and longitudinal effective confinement length, and will increase with increasing the coulomb bound potential and decreasing the electron-phonon coupling strength.