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

该奖项支持研究和教育，旨在促进我们对含有移动电子的材料的理解，这些移动电子彼此强烈相互作用，产生具有新型超导特性的新物质状态。超导是金属中许多电子的量子态，其特征是电阻的损失，从而导致所有能量的耗散。要研究的材料包括铜基和铁基超导体，以及铱系统。PI的小组将使用电子模型计算来研究几个问题，以更广泛地了解这些材料是如何工作的。特别是在不同情况下可以破坏或形成超导态的缺陷和杂质的基本物理将被研究。这些研究将使人们对高温超导的性质有更深入的了解。了解相关电子系统的特性和无序的影响可能会导致新的材料特性，这些特性可以用于新的设备和技术，在高度相关电子系统中发生的竞争相之间的转换附近获得异常的灵敏度。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，对盖恩斯维尔地区的学生进行物理教育，举行关于超导的公开和讨论会，并通过广泛的网站在公众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长期存在的淬火无序和各种类型的竞争性紧急秩序的基本问题。要研究的材料包括铜基和铁基超导体，以及铱系统。铁基超导体表现出各种各样的行为，表明电子对破坏xy对称的外部扰动的响应非常强，并且可能对超导性很重要。电子掺杂铜超导体和铁基超导体均表现出流动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对晶格上相互作用电子的简化模型的仔细分析来研究，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过渡温度以上的电子向列不稳定性的影响。为了实现研究目标，将对Hubbard模型中超导临界温度和序参量在相图上进行完整的数值和解析计算，包括自旋密度波和涨落交换相互作用近似下的共存相。

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.