Optically induced non-equilibrium spin transport in mesoscopic semiconductor circuits

介观半导体电路应进行系统的表征和探索，以实现基于此类电路中电子自旋自由度的有效信息处理。为此，一种空间分辨的自旋极化光电流映射技术应应用于gaas基异质结构的二维电子库中定义的介观电路。利用量子点接触（QPC）的自旋分裂一维子带，利用光电自旋探测器对自旋极化光电流进行局部分析。因此，非平衡自旋居群的介观自旋输运现象将在弹道和扩散状态下进行研究。特别强调将放在自旋散射过程从二维到一维自旋系统的过渡。我们进一步期望深入了解自旋轨道耦合项引起的自旋弛豫机制，即由于结构和体反转不对称。所提出的实验将为介观光电自旋器件的研究奠定基础。在SPP中，我们进一步计划将我们的共聚焦光电表征方案转移到基于inas和基于zno的电路中，以探索这些材料中的自旋极化光电流特性。

Mesoscopic semiconductor circuits shall be systematically characterized and explored to enable an efficient information processing based upon the electronic spin degree of freedom in such circuits. To this end, a spatially resolved, spin-polarized photocurrent mapping technique shall be applied to mesoscopic circuits defined in two-dimensional electron reservoirs of GaAs-based heterostructures. The spin-polarized photocurrents will be locally analyzed by an optoelectronic spin detector exploiting spin-split one-dimensional subbands of a quantum point contact (QPC). Hereby, mesoscopic spin-transport phenomena of a non-equilibrium spin population shall be explored in the ballistic and diffusive regime. Particular emphasize will be placed on spin scattering processes at the transition from a two-dimensional to a one-dimensional spin system. We furthermore expect insights into spin relaxation mechanisms induced by spin-orbit coupling terms, i.e. due to structural and bulk inversion asymmetry. The proposed experiments shall prepare ground for mesoscopic optoelectronic spin devices. Within the SPP, we further plan to transfer our confocal optoelectronic characterization scheme towards InAs-based and ZnO-based circuits in order to explore the spin-polarized photocurrent properties in these materials as well.