Studies of Transport and Many Body Effects in Strongly Correlated Frustrated Lattices

强相关受阻晶格中的传输和许多身体效应的研究

• 批准号: 0706128
• 负责人: Sriram Shastry
• 金额: $ 30万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0706128&HistoricalAwards=false
• 关键词: Studies; Transport; Many; Body; Effects

This award supports theoretical research and education that aims to elucidate the role of correlations on thermal and charge transport in unusual ordered phases of electronically frustrated systems. This work is motivated by recent discoveries of magnetism, unusual superconductivity, and anomalous transport behavior in the sodium cobalt oxide system NaxCoO2 and new organic compounds which show promise of exhibiting quantum spin liquid states.Superconductivity occurs on hydrating NaxCoO2, and is of extreme type II kind, with a puzzling symmetry. Sodium charge ordering occurs in surprising linear patterns. Unusual magnetic long-ranged order occurs in the phase diagram. Such experimental findings challenge the tenets of the basic theory of metals, suggesting the role of strong many body correlations in these systems.New ideas for computing the transport response functions have provided a direction for calculations, and yielded preliminary results that go some distance towards explaining the large thermopower, its extreme sensitivity to magnetic fields, and a linear T dependence of the Hall constant.The PI will study the transport properties and the occurrence as well as nature of the magnetic and superconducting states, in models that are appropriate to describe these systems, using a combination of analytical and numerical techniques. The main focus is to develop other techniques to further understand the many-body renormalizations underlying these systems.NON-TECHNICAL SUMMARY:This award supports theoretical research and education on a class of materials that display unusual properties that do not follow the standard textbook paradigms. It is believed that heightened interactions among electrons peculiar to these materials play an important role in understanding their properties and the unusual quantum mechanical states of their electrons. The PI will carry out theoretical research focused on understanding how charge and heat are carried by the electrons in these materials. Studying these properties can provide important clues that can contribute to a broader understanding of these unusual materials and their electronic states. The materials of particular interest involve recently discovered organic compounds and a cobalt bearing material that exhibits an unusual superconducting state where electric current can flow without dissipation. The electronic states of matter in these materials and their properties are of great fundamental interest and bear on challenging problems in the field of condensed matter physics. They are also potentially interesting from a technological point of view; devices for electric power generation and cooling are among the possible applications.

该奖项支持理论研究和教育，旨在阐明电子受阻系统异常有序相中热和电荷传输相关性的作用。这项工作的动机是最近在钴钠氧化物系统 NaxCoO2 中发现磁性、不寻常的超导性和异常输运行为，以及新的有机化合物，这些化合物有望表现出量子自旋液态。超导性发生在水合 NaxCoO2 上，并且是极端的 II 型善良，具有令人费解的对称性。钠电荷排序以令人惊讶的线性模式发生。相图中出现不寻常的磁长程有序。这些实验结果挑战了金属基本理论的原则，表明了强多体相关性在这些系统中的作用。计算传输响应函数的新想法为计算提供了方向，并产生了初步结果，在一定程度上解释了热电势大、对磁场极其敏感，以及霍尔常数的线性 T 依赖性。PI 将在适合描述这些状态的模型中研究磁态和超导态的输运特性和发生以及性质。系统，结合使用分析和数值技术。主要重点是开发其他技术，以进一步了解这些系统背后的多体重整化。非技术摘要：该奖项支持对一类材料的理论研究和教育，这些材料表现出不遵循标准教科书范式的不寻常特性。人们相信，这些材料特有的电子之间增强的相互作用对于理解它们的性质和电子的不寻常的量子力学状态发挥着重要作用。 PI 将开展理论研究，重点是了解这些材料中的电子如何携带电荷和热量。研究这些特性可以提供重要的线索，有助于更广泛地了解这些不寻常的材料及其电子态。特别令人感兴趣的材料包括最近发现的有机化合物和含钴材料，该材料表现出不寻常的超导状态，电流可以在不耗散的情况下流动。这些材料中物质的电子态及其性质具有重大的根本意义，并且涉及凝聚态物理领域的挑战性问题。从技术角度来看，它们也可能很有趣。发电和冷却设备是可能的应用之一。