Disorder and the Emergence of Inhomogeneous Phases in Strongly Correlated Electron Systems

强相关电子系统中的无序和非均匀相的出现

• 批准号: 1407502
• 负责人: Peter Hirschfeld
• 金额: $ 30万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1407502&HistoricalAwards=false
• 关键词: Disorder; Emergence; Inhomogeneous; Phases; Strongly

NON-TECHNICAL SUMMARYThis award supports research and education designed to advance our understanding of materials containing mobile electrons that interact strongly with each other, giving rise to new states of matter with novel superconductive properties. Superconductivity is a quantum state of many electrons in a metal that is characterized by the loss of electrical resistance and consequently of all dissipation of energy. The materials to be investigated include cuprate and Fe-based superconductors, as well as iridate systems. The PI's group will use model calculations for electrons to study several problems directed towards a broader understanding of how these materials work. In particular the fundamental physics of defects and impurities that can destroy or nucleate superconducting states under different circumstances will be studied. These investigations will result in a deeper understanding of the nature of high temperature superconductivity. Understanding properties of correlated electron systems and the influence of disorder may lead to novel materials properties that could be utilized in new devices and technologies, obtaining unusual sensitivity operating near transitions between competing phases that occur in highly correlated electron systems. This could have enormous technological implications. The award will support training of graduate students. The PI's group will engage in outreach activities to educate schoolchildren in the Gainesville area about physics, hold public and colloquium talks on superconductivity, and offer information on research activities at a public level through the extensive website. TECHNICAL SUMMARYThis award supports theoretical research and education to address long-standing fundamental problems of quenched disorder and various types of competing emergent order in correlated electron systems. The materials to be investigated include cuprate and Fe-based superconductors, as well as iridate systems. The Fe-based superconductors exhibit a wide variety of behavior suggesting that the electronic responses to external perturbations that break xy symmetry are extremely strong, and may be important for superconductivity. Both electron-doped cuprate superconductors and Fe-based superconductors exhibit phases where itinerant spin density wave order coexists with superconductivity. Properties of electronic states in these materials will be studied through a careful analysis of simplified models of interacting electrons on the lattice, informed in some cases by microscopic density functional theory calculations. The PI's group will also study the influence of impurities on electronic nematic instabilities in Fe-based superconducting systems at temperatures above the superconducting transition. To achieve research goals the full numerical and analytical calculations of the superconducting critical temperature and order parameter in the Hubbard model across its phase diagram, including the spin density wave and coexistence phases within a fluctuation exchange interaction approximation will be performed.

非技术摘要这一奖项支持研究和教育，旨在促进我们对包含彼此相互互动的移动电子材料的理解，从而带来了新的物质状态，并具有新颖的超导性能。 超导性是金属中许多电子的量子状态，其特征是电阻的丧失，因此是所有能量耗散的。要研究的材料包括铜酸盐和基于Fe的超导体以及偶然系统。 PI小组将使用电子模型计算来研究一些针对这些材料如何工作的广泛理解的问题。 特别是在不同情况下可以破坏或成核超导状态的缺陷和杂质的基本物理学。这些研究将使人们对高温超导性的性质有更深入的了解。了解相关电子系统的特性和疾病的影响可能会导致新的材料特性，这些特性可以在新的设备和技术中使用，从而获得了在高度相关的电子系统中发生的竞争阶段之间过渡的异常灵敏度。这可能具有巨大的技术意义。该奖项将支持研究生的培训。 PI的小组将从事外展活动，以教育盖恩斯维尔地区的学童有关物理学，举行有关超导性的公共和座谈会的会谈，并通过广泛的网站在公共层面上提供有关研究活动的信息。 技术摘要这一奖项支持理论研究和教育，以解决相关电子系统中猝灭疾病和各种类型的竞争紧急秩序的长期基本问题。要研究的材料包括铜酸盐和基于Fe的超导体以及偶然系统。 基于Fe的超导体表现出多种行为，表明对外部扰动的电子响应破裂XY对称性非常强，并且对超导性可能很重要。 电子掺杂的库酸酯超导体和基于FE的超导体都均表现出循环旋转密度波顺序的相位，并以超导性共存。 这些材料中电子状态的性质将通过对晶格上的简化相互作用的简化模型进行仔细分析，在某些情况下通过微观密度函数理论计算得出。 PI的组还将研究杂质对高于超导过渡的温度的基于Fe的超导系统中电子列不稳定性的影响。 为了实现研究目标，将在波动交换相互作用近似中执行哈伯德模型中超导临界温度和顺序参数的完整数值和分析计算，包括旋转密度波和共存阶段。