OPNMR- A Local Probe of Spin Physics

Yale University, New Haven CT

Investigators

Abstract

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.