导　　师： 史庭云

学科专业： G0205

授予学位： 博士后

作　　者： ;

机构地区： 中国科学院武汉物理与数学研究所

摘　　要： 半导体低维量子结构的研究是近年来国内外凝聚态物理的一个非常热门的领域之一，因而在理论和实验上国内外学者都进行了深入的研究。本论文研究量子环、量子点及其耦合体系，深入系统地探讨了磁场等因素对其性质的影响。全文共分为五章。
　　 第一章简要介绍量子环、量子点及其耦合体系的性质和应用，以及其理论研究方法。
　　 第二章改进了受到磁场作用的N电子量子环的理论。该理论要点是选择单个电子量子环的本征波函数的乘积态作为基矢，直接求解包含N个电子的量子环的薛定谔方程，得到定性上准确的本征解(即本征能和本征波函数)。定义了量子环体密度函数。
　　 第三章研究了包含少量电子(1至6个电子)的量子环：获得了其低态能谱随磁场的变化规律，绘制了其基态的(L0，S0)相图，利用体密度函数抽出了其电子结构的信息。
　　 第四章探讨了磁场、杂质以及限制势等因素对二维少电子量子点的低态能谱的影响；绘制了其基态的(L0，S0)相图，这些相图清晰地显示磁场、杂质、限制势对量子点基态的综合效应；此外，还获得了基态量子点的电子结构受磁场、杂质、限制势影响的规律。
　　 第五章阐述以B样条函数为基组计算二维量子环耦合体系(量子环-量子点耦合体系和量子环-量子环耦合体系)的理论方法，指出量子环和量子点都是其特例。 Research on low-dimensional quantum structures of semiconductor is one of the hot topics in condensed-matter physics in recent years, thus a great lot of researches in theory and experiment have been carried out. This paper studies quantum rings /(QRs/), quantum dots /(QDs/), and their coupling systems, and effect of factors, e.g. the magnetic field, on their properties. This thesis consists of five chapters. In chapter 1, properties and applications of QRs, QDs, and their coupling systems, as well as their theory research methods are briefly introduced. In chapter 2, theory of an N-electron QR subjected to the magnetic field is improved. The theory points are as follows: adopting product-functions of eigenfunctions of a single-electron QR as basis functions, the schrodinger equation of the N-electron QR is solved directly, and the qualitative exact eigensolutions /(the eigenenergies and eigenstates/) are obtained. Body density-functions of QRs are defined. In chapter 3, the few-electron QRs containing 1 up to 6 electrons are studied. First, evolution of the low-lying state energy against magnetic field is obtained. Secondly, the /(L/_0,S/_0/) phase diagrams of the ground states are plotted. At last, the information of the electronic structures is extracted. In chapter 4, the effect of the factors, i.e. magnetic fields, impurities, and confined potentials, on energy spectra of low-lying states of a 2-dimensional few-electron QD is discussed. The /(L/_0, S/_0/) phase diagrams of the ground states are plotted. The diagrams indicate clearly synthesized effect of the magnetic fields, the impurities and confined potentials on the ground states. Furthermore, their influence on the electronic structure of the ground states is revealed. In chapter 5, it is clarified for the theory method that two-dimensional QR coupling systems, i.e. QR- QR systems and QR- QD systems, are calculated with B-spline functions as basis, and pointed out that QRs and QDs are their examples.

关 键 词： 量子环耦合体系 凝聚态物理 量子点基态 电子结构 体密度函数

领　　域： [理学]