Quasi-1-D Molecular Organic Conductors: Experiment and Simulation

准一维分子有机导体：实验与模拟

• 批准号: 0605339
• 负责人: Michael Naughton
• 金额: $ 48万
• 依托单位: Boston College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605339&HistoricalAwards=false
• 关键词: Quasi; Molecular; Organic; Conductors; Experiment

NON-TECHNICAL:Everything in our everyday experience with electricity and electronics, from the current running through the toaster oven to the entire information technology revolution, involves electrons that don't "talk" to each other. We have learned to manipulate the electron's charge to the extent we have because we understand how they can be considered non-interacting in spite of the opposites attract, likes repel dictum. Magnetism and superconductivity are spectacular exceptions to this nontalking state, but there are others, and there is much more to learn about the electron. Much of what is new is being found when electron motion is severely confined. We already know that new phenomena arise when strict planar geometry is imposed (two-dimensionality). Realization of this condition in modern semiconducting materials led directly to the discoveries of the integer and fractional quantized Hall effects. The former involves electrons that hardly talk to each other, while for the latter, they are intimately and exquisitely engaged. The present project deals with the nature of the electron when its motion is further confined, to one dimension. There are certain organic and molecular materials that are quite good electrical conductors, and whose structural characteristics are such that the electron motion is very nearly one-dimensional. Again, as a result of geometric constrictions, and the concomitant increase in the importance of quantum mechanical effects on small size scales, new phenomena are arising, especially in strong magnetic fields. This project investigates the behavior of electrons in one-dimensional materials, in particular the nature of the recently-discovered interference-commensurate magnetoresistance oscillation phenomena discovered by the project PI. Knowledge gained from this study will be found to be of much use by technologists wishing to devise nanoscale electronic and electromagnetic structures, for example using carbon nanotubes, where one-dimensional effects will dominate. 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.TECHNICAL:This individual investigator award supports an experimental project to investigate low-dimensional conductors and superconductors. One goal of this project is to determine the origin of angular magnetoresistance oscillations in quasi-one-dimensional organic metals. Recent experiment and theory suggest a new type of macroscopic quantum effect, interference commensurate oscillations, or perhaps this is a new manifestation of a known effect. Angle-dependent magnetotransport measurements in the highest attainable fields (45 tesla at BC, 60 tesla at NHMFL) will be used to examine in detail the 1D-to-2D dimensional crossover phenomenon seen in TMTSF organic conductors. Also, using nanolithographic and microcantilever techniques, finite size effects, and their impact on spin density waves and spin-triplet superconductivity, will be explored for the first time in these materials. 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.

非技术性：我们日常生活中与电力和电子有关的一切，从烤箱中的电流到整个信息技术革命，都涉及到彼此不“交谈”的电子。 我们已经学会了在一定程度上操纵电子的电荷，因为我们知道它们是如何被认为是不相互作用的，尽管有相反的吸引，喜欢排斥的格言。 磁性和超导性是这种不说话状态的壮观例外，但还有其他的，关于电子还有更多的东西要学，很多新的东西都是在电子运动受到严格限制时发现的。 我们已经知道，当严格的平面几何（二维性）被强加时，新的现象就会出现。 在现代半导体材料中实现这一条件直接导致了整数和分数量子化霍尔效应的发现。 前者涉及的电子几乎不互相交谈，而后者，它们密切而精致地参与其中。 目前的项目涉及电子的性质时，它的运动进一步限制在一维。 有些有机材料和分子材料是很好的电导体，它们的结构特征是电子运动几乎是一维的。 同样，由于几何收缩，以及随之而来的小尺寸尺度上量子力学效应重要性的增加，新的现象正在出现，特别是在强磁场中。 该项目研究一维材料中电子的行为，特别是最近发现的干涉相称磁阻振荡现象的性质。 从这项研究中获得的知识将被发现对希望设计纳米级电子和电磁结构的技术人员非常有用，例如使用一维效应占主导地位的碳纳米管。 该项目将通过暑期实习、奖学金和研讨会，促进高中、本科和研究生等不同层次的学生对新材料物理学的学习和发现。技术：该个人研究者奖支持一个研究低维导体和超导体的实验项目。这个项目的一个目标是确定准一维有机金属中角磁阻振荡的起源。 最近的实验和理论提出了一种新型的宏观量子效应，干涉相称振荡，或者这可能是一种已知效应的新表现。 在最高可达到的领域（45特斯拉在BC，60特斯拉在NHMFL）的角度相关的磁输运测量将被用来详细研究的一维到二维的交叉现象中看到的TMTSF有机导体。 此外，使用纳米光刻和微悬臂梁技术，有限尺寸效应，以及它们对自旋密度波和自旋三重态超导性的影响，将首次在这些材料中进行探索。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新材料的物理学。