Electronic-Structure Theory of Semiconductor Quantum Dots
Electronic-Structure Theory of Semiconductor Quantum Dots
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半导体量子点的电子结构理论
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
A. Zunger
中科院分区：
文献类型：
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作者：
A. Zunger
在“独立”（例如胶体）量子点生长（另请参阅本期 Nozik 和 Micic 以及 Alivisatos 的文章）和半导体嵌入（“自组装”）量子点生长（另请参阅本期 Bimberg、Grundmann 和 Ledentsov 的文章）方面取得的进展，为量子结构的新的、令人兴奋的光谱研究打开了大门。这些揭示了丰富的、有时是意想不到的特征，例如量子点形状依赖的跃迁、吸收和发射之间尺寸依赖的（红色）转变、高激发能级的发射、表面介导的跃迁、交换分裂、应变诱导的分裂和库仑封锁跃迁。这些新的观察结果需要开发能够分析 10 3 –10 6 原子物体的电子结构的适当理论工具。主要挑战是理解（a）点的单电子能级反映量子尺寸、量子形状、界面应变和表面效应的方式，以及（b）“多粒子”相互作用的本质，例如电子-空穴交换（“红移”的基础）、电子-空穴库仑效应（激子跃迁的基础）和电子-电子库仑（库仑封锁效应的基础）。有趣的是，虽然周期固体的电子结构理论自诞生以来就以多种方法为特征（全电子与赝势；Hartree Fock 与密度泛函；创建丰富“字母汤”的计算方案，如 APW、LAPW、LMTO、KKR、OPW、LCAO、LCGO、平面波、ASW 等），但量子纳米结构理论主要由一种广泛使用的方法主导，我将其称为“标准模型”：有效质量近似 (EMA) 及其对“k·p”的扩展（其中 k 是波矢量，p 是动量）。事实上，纳米结构会议的发言者经常将其称为“理论”，而不必具体说明正在做什么。观众都知道。
Progress made in the growth of “free-standing” (e.g., colloidal) quantum dots (see also articles in this issue by Nozik and Micic, and by Alivisatos) and in the growth of semiconductor-embedded (“self-assembled”) dots (see also the article by Bimberg, Grundmann, and Ledentsov in this issue) has opened the door to new and exciting spectroscopic studies of quantum structures. These have revealed rich and sometimes unexpected features such as quantum-dot shape -dependent transitions, size-dependent (red) shifts between absorption and emission, emission from high excited levels, surface-mediated transitions, exchange splitting, strain-induced splitting, and Coulomb-blockade transitions. These new observations have created the need for developing appropriate theoretical tools capable of analyzing the electronic structure of 10 3 –10 6 -atom objects. The main challenge is to understand (a) the way the one-electron levels of the dot reflect quantum size, quantum shape, interfacial strain, and surface effects and (b) the nature of “ many-particle ” interactions such as electron-hole exchange (underlying the “red shift”), electron-hole Coulomb effects (underlying excitonic transitions), and electron-electron Coulomb (underlying Coulomb-blockade effects). Interestingly, while the electronic structure theory of periodic solids has been characterized since its inception by a diversity of approaches (all-electron versus pseudopotentials; Hartree Fock versus density-functional; computational schemes creating a rich “alphabetic soup,” such as APW, LAPW, LMTO, KKR, OPW, LCAO, LCGO, plane waves, ASW, etc.), the theory of quantum nano-structures has been dominated mainly by a single approach so widely used that I refer to it as the “Standard Model”: the effective-mass approximation (EMA) and its extension to the “k · p” (where k is the wave vector and p is the momemtum). In fact, speakers at nanostructure conferences often refer to it as “theory” without having to specify what is being done. The audience knows.