Geometrical impact on the optical polarization of droplet epitaxial quantum dots
Geometrical impact on the optical polarization of droplet epitaxial quantum dots
复制标题
液滴外延量子点光学偏振的几何影响
DOI：
10.1103/physrevb.86.115323
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发表时间：
2012
影响因子：
3.7
通讯作者：
Yu-Huai Liao
中科院分区：
文献类型：
--
作者：
秋元良裕;伊村くらら;新藤 斎;Yu-Huai Liao
本文报道了用液滴外延法生长GaAs/AlGaAs量子点的光学各向异性的实验和理论研究。在生长过程中，量子点的形状被系统地控制，从一个高的和横向对称的形状到一个平坦的和横向拉长的形状。光致发光光谱显示了一个不寻常的观察结果：量子点越长，线极化程度越低。基于四波段理论的理论分析揭示了垂直约束对价态重空穴和光空穴混合的实质性影响，从而导致高量子点极化各向异性的增强。采用部分组态相互作用方法研究了库仑相互作用对极化各向异性的影响，表明不同对称单粒子组态的混合可以降低极化各向异性。
We report on experimental and theoretical investigations of the optical anisotropy of GaAs/AlGaAs quantum dots grown by droplet epitaxy. Within situannealing in the growth, the shape of quantum dots is systematically controlled from a tall and laterally symmetric shape to a flat and laterally elongated one. Photoluminescence spectroscopy demonstrates an uncommon observation: the more elongated the quantum dots, the lower the degree of linear polarization. Theoretical analysis based on a four-bandtheory reveals a substantial impact of vertical confinement on the valence heavy-hole and light-hole mixing, which leads to the enhancement of polarization anisotropy for taller quantum dots. The influence of Coulomb interactions on polarization anisotropy is studied by using the partial configuration interaction method, and is shown to reduce the polarization anisotropy through the mixing of single-particle configurations with different symmetries.