Microscopic Theory of High Temperature Superconductivity Induced by Electronic Fluctuations

电子涨落引起的高温超导微观理论

• 批准号: 1206298
• 负责人: Chandra Varma
• 金额: $ 33万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206298&HistoricalAwards=false
• 关键词: Microscopic; Theory; Temperature; Superconductivity; Induced

TECHNICAL SUMMARYThis award supports theoretical research on a consistent microscopic theory of the extraordinary phenomena discovered in high temperature cuprate superconductors. Work done by the PI in the past two years suggests that d-wave superconductivity in cuprates comes from the quantum-critical fluctuations of the time-reversal order parameter discovered in the pseudogap region of the phase diagram and their derived coupling to fermions. In this project, the PI will work on providing definitive evidence for this suggestion by analyzing high resolution laser-angle-resolved-photoemission-spectroscopy to determine (i) the absolute magnitudes and the momentum and frequency dependence of the spectrum of fluctuations, and (ii) their coupling to fermions and variation for a range of dopings and critical temperatures. The expected outcome is the formulation of a fundamental and testable theory of the pseudo gap. In addition to this main theme, the PI and his group will undertake two new investigations on related problems: (1) Solution of Eliashberg equations for superconductivity induced by gaussian quantum-critical fluctuations, which are expected to yield results in variance with the Bardeen-Cooper-Schieffer type formulas for the energy gap, critical temperature, and thermodynamic quantities, and (2) Derivation of the multiple Higgs or amplitude modes expected in d-wave superconductors.This award also supports the education and training of a postdoctoral research associate and a graduate student in condensed matter theory. The PI will continue his active participation and mentoring activities under the University of California Leadership Excellence in Advanced Degrees and Mentoring Summer Research Internship programs. He will also participate in the Early Academic Outreach Program at this institution targeting high school students by providing various lectures and demonstrations. NON-TECHNICAL SUMMARYThis award supports theoretical research on a consistent microscopic theory of the extraordinary phenomena discovered in high temperature cuprate superconductors. These are materials discovered in the late 1980s that conduct electricity without any dissipation (no resistance, no energy loss) when they are cooled below certain critical temperatures. Even though the critical temperatures necessary for these materials to superconduct are significantly below the room temperature, they are still much higher compared to the critical temperatures of ordinary superconductors (which are close to absolute zero). Furthermore, a theory formulated in the late 1950s that explains the microscopic mechanism of superconductivity in ordinary superconductors is not adequate to explain the mechanism and physical properties of high temperature cuprate superconductors. Even though it has been 25 years since the discovery of high temperature superconductivity and many theories have been proposed, a consistent microscopic theory that explains all properties of cuprate superconductors is still missing. For the last several years, the PI and his group have been working on a theory that is consistent with most of the experimental findings. In this project, the PI will work on providing definitive evidence for his theory by analyzing the latest high resolution spectroscopy experiments. The expected outcome is the formulation of a fundamental and testable theory of an important part of the phase diagram of the cuprate superconductors. This award also supports the education and training of a postdoctoral research associate and a graduate student in condensed matter theory. The PI will continue his active participation and mentoring activities under the University of California Leadership Excellence in Advanced Degrees and Mentoring Summer Research Internship programs. He will also participate in the Early Academic Outreach Program at this institution targeting high school students by providing various lectures and demonstrations.

技术摘要这一奖项支持对高温库酸酯超导体中发现的非凡现象的一致微观理论的理论研究。 PI在过去两年中所做的工作表明，丘疹中的D波超导性来自相位图的伪甘油序区域中发现的时间反向阶参数的量子量的波动及其衍生耦合到费米子。 In this project, the PI will work on providing definitive evidence for this suggestion by analyzing high resolution laser-angle-resolved-photoemission-spectroscopy to determine (i) the absolute magnitudes and the momentum and frequency dependence of the spectrum of fluctuations, and (ii) their coupling to fermions and variation for a range of dopings and critical temperatures.预期的结果是伪差距的基本和可检验理论的制定。 除了这个主要主题外，PI和他的小组还将对相关问题进行两项新的调查：（1）解决高斯量子量子波动引起的超导性的EliAshberg方程的解决方案，预计会导致与Bardeen-Cooper-Schieffer类型的变异能量，以使能量差距，临界温度，临界温度，临界温度和热率，和2）（2）2（2）（2） D-Wave超导体预期的振幅模式。该奖项还支持博士后研究助理的教育和培训，并支持凝结物质理论的研究生。 PI将继续他的积极参与，并在加利福尼亚大学高级学位领导力和指导夏季研究实习计划的领导下进行指导。他还将通过提供各种讲座和示威活动来参加该机构的早期学术外展计划。 非技术摘要这一奖项支持对高温库酸酯超导体中发现的非凡现象的一致微观理论的理论研究。这些是在1980年代后期发现的材料，当它们冷却到某些临界温度以下时，它们在没有任何耗散的情况下进行电力而没有任何耗散（无电阻，无能量损失）。尽管这些材料对超导所需的临界温度显着低于室温，但与普通超导体的临界温度相比，它们仍然要高得多（接近绝对零）。 此外，一种在1950年代后期提出的理论解释了普通超导体中超导性的显微镜机制不足以解释高温库层超导体的机制和物理特性。 尽管已经提出了高温超导性和许多理论以来已经25年了，但一种一致的显微镜理论，即仍然缺少铜酸盐超导体的所有特性。在过去的几年中，PI和他的小组一直在研究与大多数实验发现一致的理论。在该项目中，PI将通过分析最新的高分辨率光谱实验来为其理论提供明确的证据。 预期的结果是制定了库酸酯超导体相位图的重要部分的基本和可检验理论。该奖项还支持博士后研究助理的教育和培训，以及凝结物质理论的研究生。 PI将继续他的积极参与，并在加利福尼亚大学高级学位领导力和指导夏季研究实习计划的领导下进行指导。他还将通过提供各种讲座和示威活动来参加该机构的早期学术外展计划。