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.

非技术性总结该奖项支持旨在促进我们对含有移动的电子的材料的理解的研究和教育，这些电子相互作用强烈，产生具有新颖电子性质的新物质状态。 超导性是金属中许多电子的量子状态，其特征在于电阻的损失以及因此的所有能量耗散。要研究的材料包括铜酸盐和铁基超导体，以及铱酸盐系统。 PI小组将使用电子模型计算来研究几个问题，旨在更广泛地了解这些材料的工作原理。 特别是在不同的情况下，可以破坏或成核超导状态的缺陷和杂质的基本物理将被研究。这些研究将导致对高温超导性质的更深入的理解。了解相关电子系统的性质和无序的影响可能会导致新的材料特性，可用于新的设备和技术，获得不寻常的灵敏度附近的竞争阶段之间的过渡，发生在高度相关的电子系统。这可能会产生巨大的技术影响。该奖项将支持研究生的培训。PI的小组将参与外展活动，教育盖恩斯维尔地区的学童了解物理学，举行关于超导性的公开和学术讨论会，并通过广泛的网站在公共层面提供研究活动的信息。 该奖项支持理论研究和教育，以解决相关电子系统中淬火无序和各种类型的竞争涌现秩序的长期存在的基本问题。要研究的材料包括铜酸盐和铁基超导体，以及铱酸盐系统。 铁基超导体表现出各种各样的行为，表明电子对打破xy对称性的外部扰动的响应非常强烈，并且可能对超导性很重要。 电子掺杂铜酸盐超导体和铁基超导体都表现出巡游自旋密度波序与超导性共存的相。 这些材料中的电子态的性质将通过仔细分析晶格上相互作用的电子的简化模型来研究，在某些情况下通过微观密度泛函理论计算来了解。 PI的小组还将研究杂质对铁基超导系统在超导转变温度以上的电子不稳定性的影响。 为了实现研究目标，将进行Hubbard模型中超导临界温度和序参量在其相图上的完整数值和解析计算，包括涨落交换相互作用近似中的自旋密度波和共存相。