Experimental Studies of Organic Charge Transfer Salts

有机电荷转移盐的实验研究

• 批准号: 9626291
• 负责人: Paul Chaikin
• 金额: $ 48万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-15 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9626291&HistoricalAwards=false
• 关键词: Experimental; Studies; Organic; Charge; Transfer

9626291 Chaikin A series of experiments are proposed to understand some of the basic properties of states of matter in organic conductors, and to gain insights into several current problems in condensed matter physics. For example, the Bechgaard salts are the only materials which exhibit the quantum Hall effect as a bulk three dimensional phenomenon. They are therefore unique systems for studying what happens when the conventional two dimensional electron gas layers are coupled. Questions as to the perpendicular conductivity and the coupling of edge states are open and testable. As superconductors these systems are at least as anisotropic as any others and they have much longer mean free paths. They are excellent candidates for investigating flux pinning, dynamics and Josephson vortices. Investigation also are proposed on the nature of the superconducting state. The magnetic field effects in both the"normal" metal and field induced spin density wave states have proven so unusual that there are a wealth of new phenomena to be explained. Coupled with the fact that questions of commensurability, magnetic breakdown, competing order parameters and frustration leave the limiting high field ground state an open question theoretically as well as experimentally, there is much to fuel continued excitement in this field. %%% This proposal is for continuation of a mostly experimental study of how low-dimensional strong interactions and frustration from applied fields act together to produce some quite interesting states of matter in organic conductors. The Bechgaard salts are among the most interesting electronic materials ever discovered. At room temperature they are highly anisotropic metals, but upon cooling they undergo a variety of transitions to a remarkable number of low temperature states. They were the first organic superconductors, but that is arguably their least interesting property. Depending on the anion and the pressure the ground states may be var ied from charge or spin density wave insulator to metal or superconductor. However, the properties discovered in moderate magnetic fields are even more unusual and striking. The normal metal phase also is extremely unusual showing angular dependent resonances and large magnetoresistances completely unexplainable from the known bandstructure.

9626291 Chaikin提出了一系列实验来理解有机导体中物质状态的一些基本性质，并深入了解凝聚态物理学中的几个当前问题。 例如，Bechgaard盐是唯一表现出量子霍尔效应作为体三维现象的材料。 因此，它们是研究当传统的二维电子气层耦合时会发生什么的独特系统。 垂直电导率和边缘态耦合的问题是开放的和可测试的。 作为超导体，这些系统至少和其他系统一样是各向异性的，它们的平均自由程要长得多。 它们是研究磁通钉扎、动力学和约瑟夫森涡旋的优秀候选者。 对超导态的性质也作了一些探讨.在“正常”金属和场致自旋密度波态中的磁场效应已经被证明是如此不寻常，以至于有大量的新现象需要解释。 再加上可磁化性、磁击穿、竞争序参数和挫折等问题在理论上和实验上都使极限高场基态成为一个悬而未决的问题，这一领域有很多值得继续兴奋的地方。 这个提议是为了继续一个主要是实验性的研究，研究低维强相互作用和应用领域的挫折如何共同作用，在有机导体中产生一些非常有趣的物质状态。 Bechgaard盐是迄今为止发现的最有趣的电子材料之一。 在室温下，它们是高度各向异性的金属，但在冷却时，它们会经历各种各样的转变，变成大量的低温状态。 它们是第一个有机超导体，但这可以说是它们最不有趣的特性。 根据负离子和压强的不同，基态可以从电荷或自旋密度波绝缘体到金属或超导体。 然而，在中等磁场中发现的性质更加不同寻常和引人注目。 正常的金属相也是非常不寻常的，显示出角相关的共振和大的磁阻完全无法解释从已知的能带结构。