Imaging of electron spin density in coupled semiconductor nanostructures at^3 He temperatures

半导体纳米结构的最大优点之一是电子态和自旋态可以人为设计。这使我们能够在半导体纳米结构中制备电子态，表现出新的物理特性。本研究的目的是在外部可控制的半导体奈米结构中侦测新颖的相关电子态。我们研制了低温强磁场下空间分辨圆偏振光谱系统。我们成功地研制了一台工作温度为70 mK的低温强磁场近场扫描光学显微镜。我们研究了强磁场中二维电子系统和量子点接触的成像。我们得到了宽带和窄带的图像，这可能反映了光生电子在体电子中的扩散和二维电子系统的边缘态。通过磁光致发光测量，确定了垂直磁场中1.5<rs <6范围内电子和空穴的有效质量。我们发现，所获得的有效质量的电子密度的减少而增加。在量子管中观察到光致发光峰能量的振荡依赖于通过管的磁通量。这些能量的振荡是由于量子管中带电激子的AB效应引起的。我们的研究有助于实现半导体纳米结构中新型关联电子态的外部控制。

One of the great advantages of semiconductor nanostructures is that the electronic states as well as spin states can be designed artificially. This enables us to prepare electronic states in semiconductor nanostructures which manifest novel physical properties. The purpose of this research is to detect novel correlated electronic sates in externally controllable semiconductor nanostructures. We have developed spatially resolved circularly-polarized spectroscopic system at low temperatures and at high magnetic fields. We have successfully developed a low temperature-high magnetic field-near field-scanning optical microscope operated at 70 mK. We have studied imaging of two dimensional electron system and quantum point contacts in high magnetic fields. We have obtained images of broad and narrow strips presumably reflect the diffusion of the optically created electrons in the bulk and the edge states in two dimensional electron system. We have determined of the electron and hole effective masses in perpendicular magnetic fields in the range between 1.5<r_s<6 by magneto-photoluminescence measurements. We find that the obtained effective masses increase with decrease in electron density. The oscillations of the photoluminescence peak energies are observed in quantum tubes depending on the magnetic flux through the tube. These oscillations in energies are shown to be due to the AB effect of a charged exciton in a quantum tube. Our research contributes to realize external control of novel correlated electronic sates in semiconductor nanostructures.