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

密度波相、超导性和聚合物电子传导的核磁共振研究

• 批准号: 0072524
• 负责人: W. Gilbert Clark
• 金额: $ 30万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-11-01 至 2003-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0072524&HistoricalAwards=false
• 关键词: NMR; Studies; Density; Wave; Phases

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.***

该单独的研究者奖是使用NMR授予实验研究的高级教职员工，以测量电子的微观静态和动态特性，该电子具有控制超导体，密度波材料和导电聚合物的关键特性的电子特性。该项目包括电气传输和ESR测量，通常与NMR同时同时进行。 测量将在温度，压力和磁场的极端进行。 超导性的研究包括使用NMR自旋回波进行RF诱导的通量晶格退火以及在压力下有机导体（TMTSF）（2）PF（2）PF（2）P-波超导性的测量值。 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和ESR将用于研究电子电荷传播的机制以及障碍在“金属”和金属构造多吡咯-PF中的作用（6）。 将开发有利于这项研究和较大用户社区的高频NMR仪器。 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. 许多测量值涉及高场，高频，高压和低温的极端，以及仪器的某些发展以进行。 该项目的主要目标之一是研究集体电子状态的响应，例如超导体中的涡流和准一维材料中的密度波对外部驱动力。 其他目标是在压力下探索有机超导体的异常超导状态，并确定导电聚合物中电气传导的显微镜机制。 从这项工作中获得的结果应有助于了解基本物理学，这是在技术应用中使用超导性和导电聚合物的基础。 磁共振仪器到极端的参数空间的进步将使利用这些方法的其他群体受益。 仪器技术和具有挑战性的研究问题的这种组合将为参与的学生和博士后提供宝贵的准备，以实现其未来的学术或工业职业。***