Ultrafast and time-resolved Raman spectroscopy of spin excitations in p-doped semiconductor heterostructures

我们研究了未掺杂和p掺杂的GaAsAlGaAs量子阱系统中空穴的自旋动力学和空穴基元激发的动力学。在该项目的一个部分中，我们将研究最近在低温下观察到的超长空穴-自旋相干性，讨论它对能带混合、限制势的对称性和远程掺杂的存在的依赖关系。通过时间分辨的Faraday/Kerr实验、时间分辨的光致发光和共振自旋放大，我们将探索低温和小磁场下空穴自旋的初始化机制和空穴自旋相干性的极限。在第二个项目中，我们通过拉曼光谱研究了空穴的自旋密度激发。在这里，将探索这些电荷中性自旋激发相对于不同晶体方向的各向异性以及激发的动力学。

We investigate the spin dynamics of holes and the dynamics of elementary excitations of holes in undoped and p-doped GaAs-AlGaAs quantum-well systems. In one part of the project, a very long hole-spin coherence, which we have observed recently at low temperatures, shall be studied concerning its dependence on band mixing, symmetry of the confining potential and presence of remote dopants. Employing time-resolved Faraday/Kerr experiments, time-resolved photoluminescence and resonant spin amplification, we will explore hole spin initialization mechanisms and the limits of hole spin coherence at low temperatures and small magnetic fields. In a second project part, we investigate spin-density excitations of holes via Raman spectroscopy. Here, the anisotropy of these charge-neutral spin excitations with respect to different crystal directions and the dynamics of the excitations shall be explored.