Experimental Studies of Organic Crystals, Metals and Superconductors

这个凝聚态物理项目描述了对密集、强相互作用电子系统的新研究。这些有机导体之所以引起人们的主要兴趣，是因为它们显示出不同的基态。贝克加德盐(TMTSF)2PF6等材料已经成为这些基础研究的令人兴奋的实验室。它们展示了几乎所有在其他材料中发现的凝聚电子相，以及一些新的。(TMTSF)2PF6是金属、绝缘、半金属、半导体、超导、自旋和电荷密度波，一维、二维或三维，具有场诱导自旋密度波(FISDW)态，在体相中表现出量子霍尔效应(QHE)，费米液体和非费米液体的行为随着温度、压力和磁场的变化而变化。然而，仍然有一些基本的问题仍然存在，它们是关联电子问题的核心。金属态和超导态的性质、维度交叉、可公度性、许多基态之间的竞争以及外加磁场的影响才刚刚开始被理解。这项研究涉及培训研究生和本科生使用高磁场、高压、低温和各种技术，包括运输、核磁共振、磁学和热力学测量。这项培训为学生在工业、学术或政府的职业生涯做好准备。本项目研究材料的电子性质的微观相互作用。这些实验应该会让人们更好地理解如何制造金属、绝缘体、磁铁和超导体。这些材料大多是有机晶体，因为它们可能易于制造和机械性能，但也因为它们的可变性和可控性。一个目标是回答基本问题，即晶体的结构是如何影响电子传导机制和电子相互避免的能力的。晶体的结构是平面分子的链状堆积，因此是准一维行为。电子之间的排斥力和它们的自我回避是这些晶体中发现的不同状态的原因：反铁磁体、量子霍尔导体、超导体和许多绝缘相。通过与高中生的直接接触，并通过普林斯顿材料研究所的项目，我们鼓励K-12年级的学生进行研究并参观我们的实验室。我们的工作包括对本科生、研究生和博士后进行最先进的测量和制造技术的广泛培训，从纳米光刻到高压、强磁场和低温经验。这种培训为学生在工业、学术或政府领域的职业生涯做好准备。

This condensed matter physics project describes novel investigations of dense, strongly interacting electron systems. These organic conductors are of primary interest because of the variety of ground states that they display. Materials such as (TMTSF)2PF6, a Bechgaard salt, have served as an exciting laboratory for these fundamental studies. They exhibit almost all of the condensed electronic phases discovered in other materials, and some new ones. (TMTSF)2PF6 is metallic, insulating, semi-metal, semi-conducting, superconducting, spin and charge density wave, one, two or three dimensional, with a Field Induced Spin Density Wave (FISDW) state that exhibits the quantum Hall effect (QHE) in bulk, and both Fermi liquid and non-Fermi liquid behavior as temperature, pressure and magnetic field are varied. However, there are still basic questions which remain and which are at the heart of the correlated electron problem. The nature of the metallic and superconducting states, dimensional crossover, commensurability, competition between the many ground states and the effects of applied fields are just beginning to be understood. This research involves training graduate and undergraduate students in the use of high magnetic fields, high pressures, low temperatures and a variety of techniques including transport, NMR, magnetic and thermodynamic measurements. This training prepares students for careers in industry, academe, or government.This project investigates the microscopic interactions responsible for the electronic properties of materials. The experiments should lead to a better understanding of how to make metals, insulators, magnets, and superconductors. The materials are mostly organic crystals chosen for their potential ease of fabrication and their mechanical properties but also for their variability and control. A goal is to answer fundamental questions about how the structure of the crystals, with chain like stacking of the flat molecules and hence quasi-one dimensional behaviors, influences the electron conduction mechanism and the ability of the electrons to avoid each other. The repulsion between the electrons and their self-avoidance is responsible for the different states found in these crystals: antiferromagnet, Quantum Hall conductor, superconductor, and a host of insulating phases. In direct contact with high school students and through the Princeton Materials Institute programs we encourage research and visits to our labs by K-12 students. Our work involves the extensive training of undergraduates, graduate students and postdocs in state of the art measurement and fabrication techniques, from nanolithography to high pressure, high magnetic field and low temperature experiences. This training prepares students for careers in industry, academe, or government.