Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland.
J Phys Condens Matter. 2013 Nov 20;25(46):465301. doi: 10.1088/0953-8984/25/46/465301. Epub 2013 Oct 15.
I present a systematic study of self-assembled InAs/InP and InAs/GaAs quantum dot single-particle and many-body properties as a function of the quantum dot-surrounding matrix valence band offset. I use an atomistic, empirical tight-binding approach and perform numerically demanding calculations for half-million-atom nanosystems. I demonstrate that the overall confinement in quantum dots is a non-trivial interplay of two key factors: strain effects and the valence band offset. I show that strain effects determine both the peculiar structure of confined hole states of lens type InAs/GaAs quantum dots and the characteristic 'shell-like' structure of confined hole states in the commonly considered 'low-strain' lens type InAs/InP quantum dot. I also demonstrate that strain leads to single-band-like behavior of hole states of disk type ('indium flushed') InAs/GaAs and InAs/InP quantum dots. I show how strain and valence band offset affect quantum dot many-body properties: the excitonic fine structure, an important factor for efficient entangled photon pair generation, and the biexciton and charged exciton binding energies.
我提出了一个系统的研究，研究了自组装的 InAs/InP 和 InAs/GaAs 量子点的单粒子和多体性质，作为量子点周围矩阵价带偏移的函数。我使用原子的、经验的紧束缚方法，并对五百万原子纳米系统进行数值上的要求很高的计算。我证明了量子点中的整体限制是两个关键因素的复杂相互作用：应变效应和价带偏移。我表明，应变效应决定了透镜型 InAs/GaAs 量子点中束缚空穴状态的特殊结构和通常认为的“低应变”透镜型 InAs/InP 量子点中束缚空穴状态的特征“壳状”结构。我还证明，应变导致盘型（“铟冲洗”）InAs/GaAs 和 InAs/InP 量子点中空穴状态的单带行为。我展示了应变和价带偏移如何影响量子点的多体性质：激子精细结构，这是有效产生纠缠光子对的一个重要因素，以及双激子和带电激子的结合能。
