NMR Studies of Density Wave Phases, Superconductivity, and Polymer Electronic Conduction

这一个人研究人员奖授予一名高级教员，以表彰其使用核磁共振技术测量电子的微观静态和动态特性的实验研究，这些特性支配着超导体、密度波材料和导电聚合物的关键特性。该项目包括电子传输和ESR测量，通常与核磁共振同时进行。测量将在温度、压力和磁场的极端情况下进行。在超导性方面的研究包括利用核磁共振自旋回波的射频感应磁通晶格退火法和测量有机导体(TMTSF)(2)PF(6)在压力下的明显p波超导电性。关于密度波材料的实验将包括研究(TMTSF)(2)Pf(6)在加压下的磁场诱导自旋密度波(SDW)相，研究(TMTSF)(2)P(1-x)As(X)F(6)中低于4K的热SDW相子，以解决解释SDW的矛盾，以及重新定位动力学的测量。核磁共振和电子自旋共振将被用来研究“金属”和金属绝缘的聚吡咯-PF(6)中电子电荷传播的机制和无序的作用。将开发有利于这项研究和更大用户社区的高频核磁共振仪器。仪器技术和具有挑战性的研究问题的结合将为参与的学生和博士后为他们未来的学术或工业职业生涯提供宝贵的准备。%这一个人研究人员奖授予一名高级教职员工，该项目利用核磁共振、电子自旋共振和电子传输来研究几种材料中电子的性质，如超导体、密度波系统和导电聚合物。许多测量涉及高场、高频、高压和低温的极端情况，以及执行这些测量的仪器的一些发展。这个项目的主要目标之一是研究集体电子态，如超导体中的涡旋和准一维材料中的钉扎密度波，对外部驱动力的响应。其他目标是探索有机超导体在压力下的不寻常超导状态，并确定导电聚合物中导电的微观机制。从这项工作中获得的结果应该有助于了解构成在技术应用中使用超导和导电聚合物的基础的基本物理知识。磁共振仪器发展到参数空间的极值，将使其他利用这些方法的小组受益。仪器技术和具有挑战性的研究问题的结合将为参与的学生和博士后为他们未来的学术或工业生涯提供宝贵的准备。*

This individual investigator award is to a senior faculty member for experimental investigations using NMR to measure the microscopic static and dynamic properties of the electrons that govern the key properties of superconductors, density wave materials, and conducting polymers. The project includes electrical transport and ESR measurements, often concurrently with the NMR. The measurements will be performed at extremes of temperature, pressure, and magnetic field. The studies in superconductivity include rf-induced flux lattice annealing using NMR spin echoes and measurements of apparently p-wave superconductivity in the organic conductor (TMTSF)(2)PF(6) under pressure. Experiments on density wave materials will include the study of the magnetic field-induced spin-density wave (SDW) phase of (TMTSF)(2)PF(6) under pressure, investigation of thermal SDW phasons below 4 K in (TMTSF)(2)P(1-x)As(x)F(6) to resolve the conflict in interpreting the SDW, and measurement of repinning dynamics. NMR and ESR will be used to investigate the mechanisms for electron charge propagation and the role of disorder in "metallic" and metal-insulating polypyrrole-PF(6). High frequency NMR instrumentation that benefits this research and the larger user community will be developed. This mix of instrumentation techniques and challenging research problems will provide valuable preparation of the participating students and postdocs for their future academic or industrial careers.%%%This individual investigator award is to a senior faculty member for a project that uses nuclear magnetic resonance, electron spin resonance, and electrical transport to study the properties of electrons in several materials, such as superconductors, density wave systems, and an electrically conducting polymer. Many of the measurements involve extremes of high field, high frequency, high pressure, and low temperatures, along with some development of the instrumentation to carry them out. One of the major goals of this project is to investigate the response of collective electron states, such as vortices in superconductors and pinned density waves in quasi one-dimensional materials, to an external driving force. Other goals are to explore the unusual superconducting state of an organic superconductor under pressure and to determine the microscopic mechanisms of electrical conduction in a conducting polymer. Results gained from this work should contribute to knowledge of the basic physics that forms the underpinning for using superconductivity and conducting polymers in technical applications. The advances of magnetic resonance instrumentation into extremes of parameter space will benefit other groups exploiting these methods. This mix of instrumentation techniques and challenging research problems will provide valuable preparation of the participating students and postdocs for their future academic or industrial careers.***