量子点中束缚极化子性质的温度依赖性

采用线性组合算符和幺正变换方法研究抛物量子点中弱耦合束缚极化子性质的温度依赖性,导出了弱耦合束缚极化子的振动频率、基态能量和声子平均数随温度的变化关系。取ZnS晶体为例进行数值计算,结果表明:量子点中弱耦合束缚极化子的振动频率、基态能量和声子平均数随温度的升高而增大。

Temperature Dependence of the Properties of Bound Polaron in a Quantum Dot

With the flying development of nanotechnology,the studies on the low dimension system have been greatly improved,especially on the nano semiconductor quantum dot.Since its newly opto-electric and transportation characteristics,it is becoming a heat field in the study of quantum fanctional device.Since 1980s,Tokuda has investigated the bounding polaron in the Coulombic field using LLP variational method.More and more people pay attention to the field of bounding polaron,which is not only bound by the hydrogen but also interact with LO phonon in the ionic crystal or polar semiconductor.Some anothers also use other kinds of methods to investigate the properties of bound polaron in quantum dot theoretically and expercmentally.The vibrational frequency,the ground state energy,the interaction en-ergy and the average number of optical phonons of the bound polaron in a quantum dot have been discussed using the linear combination operator method by the present authors.However,the influences of the temperature on the properties of bound polaron in a quantum dot has not been investigated so far.In fact,the case of a finite temperature is more significant.The influences of the temperature on the properties of weak-coupling bound polaron in a quantum dot are studied.The vibrational frequency,the ground state energy and the mean number of the phonons of the weak-coupling bound polaron in a quantum dot are derived by using the linear combination operator and the unitary transformation method.The temperature dependence of the vibrational frequency,the ground state energy and the mean number of the phonons of the weak-coupling bound polaron in a quantum dot are discussed.Nume-rical calculations,for the ZnS crystal as an example,are performed and the results indicate that the vibrational frequency,the ground state energy and the mean number of the phonons of the weak-coupling bound polaron in a quantum dot will increase with increasing the temperature.The ground state energy of bound polaron will increase strongly with increasing the confinement strength of the quantum dot.