非对称量子点中弱耦合极化子的相互作用能

采用改进的线性组合算符和幺正变换方法,研究非对称量子点中弱耦合极化子的性质.导出了非对称量子点中弱耦合极化子的振动频率和相互作用能随量子点的横向和纵向有效受限长度和电子-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极化子的振动频率和相互作用能随量子点的横向和纵向有效受限长度的减小而迅速增大,表现出奇特的量子尺寸效应.

Interaction Energy of Weak Coupling Polaron in an Asymmetric Quantum Dot

With the advance in the nanofabrication technology,there has been a great deal of interest in the investigating of quasi-zero-dimensional electronic systems(quantum dots).Since its newly opto-electric and electron transport characteristics,it is becoming a heat field in the study of quantum fanctional device.Many investigators studied the properties of the polaron in a quantum dots in many aspects by a variety of theoretical and experimental methods.Recently,the properties of strong and weak-coupling of the polaron in an asymme-tric quantum dot have been studied using the linear-combinating operator method by the present authors.However,using improved linear combination operator method,the properties of the polaron in an asymmetric quantum dot has not been investigated so far.In this paper,the properties of the vibrational frequency and the interaction energy of weak-coupling polaron in an asymmetric quantum dot were studied by using a improved linear combination operator and unitary transformation method.The relations of the vibrational frequency and the interaction energy of the weak coupling polaron in an asymmetric quantum dot with the transverse and the longitudinal effective confinement length of the quantum dot and the electron-phonon coupling strength are derived.If the units have been chosen in the usual polaron units(2m=h=ω_LO=1),we perform a numerical calculation.The results show that the vibrational frequency and the interaction energy of the weak coupling polaron in an asymmetric quantum dot will increase strongly with decreasing the transverse and longitudinal effective confinement length of quantum dot.Those attributed to interesting quantum size effects also appear.The interaction energy of weak coupling polaron in an asymmetric quantum dot will decrease with increacing the electron-phonon coupling strength.