OPNMR- A Local Probe of Spin Physics

在低温和强磁场下，由于强相互作用、降维、无序和量子涨落的综合作用，量子半导体异质结中的电子呈现出各种有趣的相(如量子霍尔态)。对电子自旋磁化强度和自旋动力学的测量为了解这些新的状态提供了重要的见解。该项目将使用光泵核磁共振光谱学在原子长度尺度上直接测量这些量。OP核磁共振测量将朝着新的方向发展，以解决新出现的问题，例如：(1)当Skyrmions局域化时会发生什么？以及(2)电子的“条纹”和“气泡”相是什么？开展这项研究活动的本科生和研究生将接受培训，同时使用先进的仪器，如独特的核磁共振磁体(由NSF的核磁共振计划支持)。这项拟议的研究通过教学和外展被整合到PI的教育活动中。今天的计算机使用的是利用电子电荷处理信息的电子电路。随着电路尺寸迅速接近其可能的最小尺寸，替代技术的开发变得更加重要。一种方法是希望利用电子的内在磁性，即所谓的“自旋”，来制造新型设备(“自旋电子学”)，甚至是一种功能强大的新型计算机(“量子计算机”)。为了实现这些长期目标，必须开发位于半导体内部的电子自旋的局部探测器。这项研究项目将极大地扩展一种名为光泵核磁共振(OPNMR)光谱学的探测器的能力。这些扩展将由对相互作用电子系统在低温和强磁场下的新相性质的基础研究的追求推动。进行这项研究的本科生和研究生将接受培训，同时使用先进的仪器，如独特的核磁共振磁体(由NSF的核磁共振支持)。通过教学和外展，研究活动融入了国际和平协会的教育活动。

At low temperatures and at high magnetic fields, electrons in quantum semiconductor heterostructures exhibit a wide variety of interesting phases (e.g., quantum Hall states), due to the combined effects of strong interactions, reduced dimensionality, disorder, and quantum fluctuations. Measurements of the electron spin magnetization and spin dynamics provide important insights into these novel states. This project will directly measure these quantities, on atomic length-scales, using optically pumped nuclear magnetic resonance (OPNMR) spectroscopy. The OPNMR measurements will move in new directions to address emerging questions, e.g., (1) what happens as skyrmions localize?, and (2) what are the electron "stripe" and "bubble" phases? The undergraduate and graduate students who carry out this research activity will receive training while working with advanced instruments, such as a unique NMR magnet (supported by NSF's MRI program). The proposed research is integrated into the PI's educational activities, through teaching and outreach.Today's computers use electronic circuits that process information using the electron's charge. As circuit dimensions are rapidly approaching their smallest possible size, the development of alternative technologies becomes even more important. One approach hopes to make use of the intrinsic magnetism of electrons known as "spin", to build new kinds of devices ("spintronics"), or even a powerful new class of computers ("quantum computers"). To reach these long-term goals, it is imperative to develop local probes of electron spins located inside a semiconductor. This research project will greatly extend the capabilities of one such probe, called optically pumped nuclear magnetic resonance (OPNMR) spectroscopy. These extensions will be driven by the pursuit of fundamental research into the properties of novel phases of an interacting electron system, at low temperature and in strong magnetic fields. The undergraduate and graduate students who carry out this research will receive training while working with advanced instruments, such as a unique NMR magnet (supported by NSF's MRI). The research activity is integrated into the PI's educational activities, through teaching and outreach.