Molecular Organic Conductors: Triplet Superconductivity and Novel Angular Magnetoresistance Effects

有机分子导体：三重态超导和新型角磁阻效应

• 批准号: 0308973
• 负责人: Michael Naughton
• 金额: $ 36万
• 依托单位: Boston College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0308973&HistoricalAwards=false
• 关键词: Molecular; Organic; Conductors; Triplet; Superconductivity

This individual investigator award supports an experimental project to investigate organic superconductors. One goal of this project is to determine the pairing symmetry in the quasi-one dimensional TMTSF superconductors, which a growing body of evidence suggests to be spin triplet in nature. A novel sample preparation technique will be employed to facilitate tunnel junction experiments aimed at measuring the energy gap and its anisotropy in momentum space, an essential quantity that has avoided detection for almost a quarter of a century. The goal is to determine which type of triplet state describes the pairing in these materials, p- or f-wave. This will be done via conductance measurements in a 10 mK, 13 kbar, 13 T, (temperature, pressure, magnetic field) environment. Another goal is to test a new "interference commensurate" model for the angular magnetoresistance oscillations seen in the normal metal state of the TMTSF conductors. In this model, for specific sample orientations in a magnetic field, quantum interference effects between electron waves in neighboring Brilluoin zones contribute to the electrical conductivity, and lead to novel changes of dimensionality. These experiments will also employ a 45T pulsed field magnet. The project will promote student learning and discovery of the physics of novel materials at several levels, high school, undergraduate, and graduate, through summer internships, fellowships and workshops.Magnetism is known to be the archenemy of superconductivity. This is one limitation on the resolution of MRI instruments, for example, which employ superconductors to generate strong magnetic fields. But what if it were possible to discover a route to detente between these rivals? In this project, evidence for the existence of a special form of superconductivity known as "spin triplet", in conjunction with an observed imperviousness of superconductivity to magnetism, will be sought in certain molecular organic conductors. These are among the most interesting electronic materials in our world, showing nearly every possible conducting property known: superconductor, metal, semiconductor, insulator, all in the same specimen. If they can be proven to be spin triplet (a rare, perhaps even unprecedented occurrence in nature), an important mechanism by which magnetism suppresses superconductivity will be taken away, allowing researchers to dream of schemes toward capitalizing on superconductivity's newfound immunity from magnetism. The project will promote student learning and discovery of the physics of such novel materials at several levels, high school, undergraduate, and graduate, through summer internships, fellowships and workshops.

这个个人研究者奖支持一个研究有机超导体的实验项目。 这个项目的一个目标是确定准一维TMTSF超导体中的配对对称性，越来越多的证据表明它本质上是自旋三重态。 一种新的样品制备技术将被用来促进隧道结实验，旨在测量能隙及其在动量空间的各向异性，一个基本的数量，避免了近四分之一的世纪的检测。 目标是确定哪种类型的三重态描述了这些材料中的配对，p波或f波。这将通过在10 mK、13 kbar、13 T（温度、压力、磁场）环境中进行电导测量来完成。 另一个目标是测试一个新的“干扰相称”模型的角磁阻振荡中看到的正常金属状态的TMTSF导体。 在这个模型中，对于特定的样品在磁场中的取向，在相邻的布里渊区的电子波之间的量子干涉效应有助于电导率，并导致新的变化的维度。 这些实验还将使用45T脉冲场磁体。 该项目将通过暑期实习、奖学金和研讨会，促进高中、本科和研究生几个层次的学生学习和发现新材料的物理学。众所周知，磁性是超导性的大敌。 这是MRI仪器分辨率的一个限制，例如，使用超导体产生强磁场。 但是，如果有可能找到一条缓和这些竞争对手之间关系的途径呢？ 在这个项目中，将在某些分子有机导体中寻找被称为“自旋三重态”的特殊形式的超导性存在的证据，以及观察到的超导性对磁性的不渗透性。 这些是我们世界上最有趣的电子材料之一，几乎展示了所有已知的导电特性：超导体，金属，半导体，绝缘体，都在同一个样品中。 如果它们能够被证明是自旋三重态（自然界中罕见的，甚至可能是前所未有的），那么磁性抑制超导性的一个重要机制将被带走，使研究人员能够梦想利用超导性对磁性的新发现的免疫力的计划。 该项目将通过暑期实习、奖学金和研讨会，促进学生在高中、本科和研究生等多个层次学习和发现这种新型材料的物理学。