Low-Energy Spectroscopy of Correlated Systems

相关系统的低能谱学

• 批准号: 9705442
• 负责人: Zack Schlesinger
• 金额: $ 25.5万
• 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: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9705442&HistoricalAwards=false
• 关键词: Low; Energy; Spectroscopy; Correlated; Systems

9705442 Schlesinger This is a new project to study systems in which the effects of electron interactions extend the physics beyond the domain of simple non-interacting theories of solids. For such systems there is generally a characteristic energy scale in the infrared which separates a strongly correlated low-energy region from a high-energy region in which interaction effects are much less significant. The proposed research seeks to use spectroscopic measurements to probe the dynamics in this crucial infrared range and thereby to develop an understanding of correlated systems. Specific systems to be studied include Kondo insulators, mixed-valent systems, metal- insulator transitions driven by magnetic order, and superconductor- insulator transition systems. These experiments will elucidate the nature of the charge dynamics in these systems, and explore crucial relationships between charge dynamics, magnetism, disorder and localization. Results will provide both a test of and a stimulus for theoretical work in this area at the forefront of condensed matter physics. %%% This is a new project to study systems in which the effects of electron interactions extend the physics beyond the domain of simple non-interacting theories of solids. Although our basic understanding of metals and semiconductors is built on theories of non-interacting electrons, future electronic technologies will increasingly include materials in which interactions between electrons play a role. It is thus important to fully understand the electronic properties of these correlated electron systems, in which phenomena occur that cannot be readily predicted from a knowledge of the system components (the electrons and nuclei), but rather, arise in a non-obvious way from the interactions between them. (Examples include magnetism and superconductivity.) This proposal is directed toward the study o f electron dynamics in the infrared spectral region, which encompasses the energy range relevant to the formation of most correlated electron states and is thus particularly important. Systems to be studied include rare-earth compounds that can be viewed as correlated semiconductors, and oxide systems where an interplay between magnetism and electrical conductivity leads to striking effects (e.g., giant magnetoresistance). The experimental results can be expected to stimulate and test theoretical efforts in this area at the forefront of condensed matter physics. ***

[705442 .施莱辛格]这是一个研究系统的新项目，其中电子相互作用的影响将物理学扩展到简单的非相互作用固体理论的领域之外。对于这样的系统，通常在红外中存在一个特征能量尺度，它将强相关的低能区与相互作用不太显著的高能区分开。提出的研究旨在利用光谱测量来探测这一关键红外范围内的动力学，从而发展对相关系统的理解。要研究的具体系统包括近藤绝缘体、混合价系统、由磁序驱动的金属-绝缘体过渡以及超导体-绝缘体过渡系统。这些实验将阐明这些系统中电荷动力学的本质，并探索电荷动力学、磁性、无序和局域化之间的重要关系。研究结果将为凝聚态物理前沿领域的理论工作提供检验和激励。这是一个研究系统的新项目，其中电子相互作用的影响将物理学扩展到简单的非相互作用固体理论的领域之外。虽然我们对金属和半导体的基本理解是建立在非相互作用电子的理论基础上的，但未来的电子技术将越来越多地包括电子之间相互作用发挥作用的材料。因此，充分理解这些相关电子系统的电子特性是很重要的，在这些系统中，现象的发生不能轻易地从系统组件（电子和原子核）的知识中预测，而是以一种不明显的方式从它们之间的相互作用中产生。（例子包括磁性和超导性。）这一建议是针对红外光谱区域的电子动力学的研究，该区域包含了与大多数相关电子态形成相关的能量范围，因此特别重要。要研究的系统包括稀土化合物，它可以被视为相关半导体，以及磁性和导电性之间的相互作用导致惊人效应的氧化物系统（例如，巨磁阻）。实验结果有望激发和测试凝聚态物理前沿领域的理论努力。＊＊＊