Molecular Organic Conductors: Triplet Superconductivity and Novel Angular Magnetoresistance Effects

这个个人研究者奖支持一个研究有机超导体的实验项目。该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，这种对称性在本质上是自旋三重态。一种新的样品制备技术将用于隧道结实验，旨在测量动量空间中的能量间隙及其各向异性，这是近四分之一世纪以来避免检测的重要量。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波还是f波。这将通过在10 mK， 13 kbar, 13 T（温度，压力，磁场）环境下的电导测量来完成。另一个目标是测试一种新的“干涉相称”模型，用于在TMTSF导体正常金属状态下观察到的角磁阻振荡。在该模型中，对于磁场中特定的样品取向，邻近布里渊区的电子波之间的量子干涉效应有助于电导率，并导致新的维数变化。这些实验还将使用45T脉冲磁场磁铁。该项目将通过暑期实习、奖学金和研讨会，促进学生在高中、本科和研究生等不同层次上对新材料物理学的学习和发现。众所周知，磁性是超导性的大敌。这是核磁共振成像仪器分辨率的一个限制，例如，它使用超导体来产生强磁场。但如果有可能找到缓和这两个对手关系的途径呢？在这个项目中，将在某些分子有机导体中寻找一种特殊形式的超导性存在的证据，这种超导性被称为“自旋三重态”，并结合观察到的超导性对磁性的不渗透性。这些是我们这个世界上最有趣的电子材料之一，几乎展示了所有已知的可能的导电特性：超导体、金属、半导体、绝缘体，所有这些都在同一个样品中。如果它们可以被证明是自旋三重态（这在自然界是罕见的，甚至可能是前所未有的），那么磁性抑制超导性的重要机制将被剥夺，使研究人员能够梦想利用超导性新发现的磁性免疫的方案。该项目将通过暑期实习、奖学金和研讨会，促进学生在高中、本科和研究生等不同层次上对这些新材料的物理学的学习和发现。

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.