磁场和抛物势对半指数量子阱极化子振动频率的影响  

The Influences of a Magnetic Field and Anisotropic Parabolic Potential on the Vibrational Frequency of Polaron in Asymmetrical Semi-exponential Quantum Wells

作　　者：戈君[1] 肖景林[2] GE Jun;XIAO Jing-lin(College of Physics and Electronic Information,Inner Mongolia Hulunber'er College,Hulunber'er 021008,China;Institute of Condensed Matter Physics,Inner Mongolia University for the Nationalities,Tongliao 028043,China)

机构地区：[1]内蒙古呼伦贝尔学院物理与电子信息学院,内蒙古呼伦贝尔021008 [2]内蒙古民族大学凝聚态物理研究所,内蒙古通辽028043

出　　处：《量子光学学报》2021年第2期157-162,共6页Journal of Quantum Optics

基　　金：国家自然科学基金(11464033);内蒙古自治区高校科学研究(NJZY13324)。

摘　　要：量子阱由于受到受限势的限制作用会体现出特殊的物理特性,在实验中发现量子阱的生长方向受限势必须是强受限势而另外两个方向为非强受限势,所以本文在量子阱的生长方向施加非对称半指数受限势构成了非对称半指数势量子阱,为了深入了解非对称半指数量子阱的结构特征,在其垂直量子阱的生长方向施加各向异性抛物势,同时又增加了磁场对量子阱中电子的限制作用,研究了磁场对该量子阱中弱耦合极化子的影响。通过两次幺正变换和线性组合算符推导出弱耦合极化子的振动频率随抛物势的x与y方向的受限强度、磁场的回旋频率及非对称半指数受限势的两个参数的变化关系。并以处在非对称半指数量子阱中的GaAs半导体晶体进行模拟计算,结果表明:当x与y方向的受限强度及磁场的回旋频率取定值时非对称半指数量子阱中弱耦合极化子的振动频率是受限势参量U0的增函数,而它是另一个参量σ的减函数,参数的改变是电子声子间耦合加强促进了极化子的形成。当磁场回旋频率及参量U0和σ取定值时,极化子的振动频率是各向异性抛物势的x方向和y方向的受限强度的增函数,这体现了量子的尺寸限制效应,此外,由于磁场回旋频率随磁场的增大而增大,磁场回旋频率增大时会使极化子受到更强的约束作用,所以振动频率加强。当y方向的受限强度及参量U0和σ取定值时极化子的振动频率是磁场的回旋频率的增函数。Due to quantum wells new physical properties under the constrained potential limitation on the electron,there is a confined potential along QW growth directions and it must be a strong confined potential. By adding an asymmetrical semi-exponential potential in the QW’s growth direction, asymmetrical semi-exponential quantum well is formed. In order to deepen the understanding of the structural characteristics of asymmetrical semi-exponential quantum well, an anisotropic parabolic potential perpendicular to the growth direction of the quantum well was added,at the same time, the confinement of the magnetic field to the electrons in the quantum well is increased, the influences of magnetic field on the properties of the vibrational frequency of the weak-coupling polaron in a GaAs asymmetrical semi-exponential quantum well is studied. The vibrational frequency of the weak-coupling polaron in a GaAs asymmetrical semi-exponential quantum well varying with the two parameters of the asymmetrical semi-exponential confinement potential, the cyclotron frequency of the magnetic field and the confinement strengths of anisotropic parabolic potential in the x and y directions is derived by using linear combination operator and the unitary transformations methods. The numerical calculated results are indicated for a typical GaAs semiconductor asymmetrical semi-exponential quantum well crystal. It is founded that the vibrational frequency of the weak-coupling polaroa in a asymmetrical semi-exponential quantum well is a lifting function of the parameter U0, whereas it is a decaying one of the other parameter σ, when the anisotropic parabolic potential in the x and y directions and the cyclotron frequency of the magnetic field are fixed, the coupling between electron and phonon is strengthened and the formation of polaron is promoted by the change of parameters. The vibrational frequency of the polaron increases with the confinement strengths of anisotropic parabolic potential in the x and y directions when the cyclotron freque

关 键 词：非对称半指数量子阱 弱耦合极化子 振动频率 磁场 各向异性抛物势 线性组合算符 

分 类 号：O469[理学—凝聚态物理]