半導體量子環的等效電洞g因子以及光學異向性

Abstract

半導體奈米結構中電洞之自旋被認為非常合適做為量子資訊的量子位元，對於使用自旋，能夠控制自旋的能量匹裂，也就是控制量子系統的g因子是不可或缺的技術。 在本篇論文中利用數值方法，研究量子環系統中電子結構、電洞等效g因子以及光學異向性等特性，並考慮兩種形狀異向性，高度異向性以及半徑異向性。使用k.p多能帶理論進行數值計算和理論分析。結果顯示量子環不對稱性會增加xy平面平行方向電洞g因子的大小，高度異向性以及半徑異向性對於量子環電洞g因子會產生方向相異的不對稱性。光學偏振上，z方向發光之偏振在不對稱性影響下，呈現和電洞g因子不同的極化趨勢。

The spin of hole confined in a semiconductor nanostructure is considered as a quantum bit(Q-bit) for quantum information technology. In spin-based quantum technology, manipulating the spin-splitting, characterized by effective g-factor is necessary. In this work, I theoretically investigate the energy spectra, effective hole g-factor and optical polarization of quantum ring with anisotropic ring height and lateral elongation, respectively. Numerical results and theoretical analysis are based on k.p multi-band theory. Results show that both magnitude of the in-plane hole g-factor will be changed by increasing the structural asymmetry. Furthermore, anisotropic ring height and lateral elongation induce different anisotropy for in-plane hole g-factor. On the other hand, the effect of the structural asymmetry will induced different anisotropic properties between the optical polarization and hole g-factor.