Physics of Non-Fermi Liquid Metals

非费米液态金属物理学

• 批准号: 1920740
• 负责人: Qimiao Si
• 金额: $ 42万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1920740&HistoricalAwards=false
• 关键词: Physics; Non; Fermi; Liquid; Metals

NONTECHNICAL SUMMARYThis award supports theoretical research and education in the many-body physics of strongly correlated quantum materials. The textbook description of electrons in solids assumes essentially free electrons, moving throughout the solid independently of what all other electrons are doing. Research in the recent past has shown that this description fails in a wide variety of materials, in which electrons in the solid are strongly correlated with each other. In these quantum materials, strong correlations can produce unusual states of matter, and lead to phase transitions between them. These are the quantum analogues of familiar phase transitions such as ice melting into water, or water boiling into vapor. The PI will develop theoretical methods to study the collective behavior of electrons near such phase transitions to understand how novel types of superconductivity can be generated, and to explore how these states evolve under the influence of external electromagnetic fields.Through the project, the PI will bring about understanding about quantum materials in general, which is a central element of quantum science and technology that has recently emerged as a top national priority. The PI intends to collaborate with leading experimental groups worldwide in this area, thereby creating educational opportunities for graduate and undergraduate students involved in the PI's research program. The advanced theoretical training will help students prepare for future careers in academia or industry.TECHNICAL SUMMARYThis award supports theoretical research and education in the physics of strongly correlated quantum materials. Strong correlations can yield novel phases and unusual excitations. In metallic systems, an outstanding challenge is to understand how the correlations generate physics beyond the Fermi-liquid theory. The proposed research will address this open problem, primarily by using systems with both itinerant electrons and localized moments as a prototype setting. The research will develop and apply controlled theoretical methods to study well-defined microscopic and field-theory models. The research aims to gain new insights that are broadly relevant to the physics of strongly correlated electrons. The PI will pursue four specific research directions: First, the PI will analyze heavy-fermion quantum criticality, with a focus on Kondo lattice systems that contain entwined degrees of freedom. Second, the PI plans to initiate theoretical studies on the novel phases that emerge near quantum critical points, including pairing state of multiorbital superconductivity that is driven by quantum criticality. Third, the PI will explore non-Fermi-liquid physics in heavy-fermion systems potentially hosting Kondo-driven Weyl nodes, thereby elucidating quantum criticality in a new setting. Fourth, the PI will investigate real-time dynamics under driven conditions as a means of probing quantum criticality. Through concrete model studies, this research direction aims to shed light on the coherence and dynamics of strongly coupled quantum systems out of equilibrium.Through the project, the PI will bring about understanding about quantum materials in general, which is a central element of quantum science and technology that has recently emerged as a top national priority. The PI intends to collaborate with leading experimental groups worldwide in this area, thereby creating educational opportunities for graduate and undergraduate students involved in the PI's research program. The advanced theoretical training will help students prepare for future careers in academia or industry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术总结该奖项支持强相关量子材料的多体物理学的理论研究和教育。教科书对固体中电子的描述基本上是假设自由电子在固体中运动，与其他电子的运动无关。最近的研究表明，这种描述在各种各样的材料中都失败了，其中固体中的电子彼此之间有很强的相关性。在这些量子材料中，强关联可以产生不寻常的物质状态，并导致它们之间的相变。这些是熟悉的相变的量子类似物，例如冰融化成水，或水沸腾成蒸汽。PI将开发理论方法来研究电子在这种相变附近的集体行为，以了解如何产生新型的超导性，并探索这些状态如何在外部电磁场的影响下演变。通过该项目，PI将从总体上理解量子材料，这是量子科学和技术的核心要素，最近已成为国家的首要任务。PI打算与世界领先的实验团体在这一领域的合作，从而创造参与PI的研究计划的研究生和本科生的教育机会。高级理论培训将帮助学生为未来在学术界或工业界的职业生涯做好准备。技术总结该奖项支持强相关量子材料物理学的理论研究和教育。强相关性可以产生新的相位和不寻常的激励。在金属系统中，一个突出的挑战是理解相关性如何产生超越费米液体理论的物理学。拟议的研究将解决这个开放的问题，主要是通过使用系统与巡回电子和本地化的时刻作为原型设置。该研究将开发和应用控制理论方法来研究定义明确的微观和场论模型。该研究旨在获得与强相关电子物理学广泛相关的新见解。PI将致力于四个具体的研究方向：首先，PI将分析重费米子量子临界性，重点是包含Enhancement自由度的Kondo晶格系统。其次，PI计划启动对量子临界点附近出现的新相的理论研究，包括由量子临界驱动的多轨道超导的配对态。第三，PI将探索可能存在近藤驱动外尔节点的重费米子系统中的非费米液体物理，从而阐明新环境中的量子临界性。第四，PI将研究驱动条件下的实时动力学，作为探测量子临界性的一种手段。通过具体的模型研究，该研究方向旨在阐明强耦合量子系统的相干性和动力学。通过该项目，PI将从总体上理解量子材料，这是量子科学和技术的核心要素，最近成为国家的首要任务。PI打算与世界领先的实验团体在这一领域的合作，从而创造参与PI的研究计划的研究生和本科生的教育机会。高级理论培训将帮助学生为未来在学术界或工业界的职业生涯做好准备。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Weyl-Kondo semimetals in nonsymmorphic systems

• DOI: 10.1103/physrevb.101.075138
• 发表时间: 2020-02-28
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Grefe, Sarah E.;Lai, Hsin-Hua;Si, Qimiao
• 通讯作者: Si, Qimiao

Hall-coefficient diagnostics of the surface state in pressurized SmB6

• DOI: 10.1103/physrevb.101.125116
• 发表时间: 2019-09
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Yazhou Zhou;P. Rosa;Jing Guo;Shu Cai;R. Yu;Sheng Jiang;Ke Yang;Aiguo Li;Q. Si;Qi Wu

Critical local moment fluctuations and enhanced pairing correlations in a cluster Anderson model

• DOI: 10.1103/physrevb.101.014452
• 发表时间: 2020-01-31
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Cai, Ang;Pixley, J. H.;Si, Qimiao
• 通讯作者: Si, Qimiao

Dynamical Scaling of Charge and Spin Responses at a Kondo Destruction Quantum Critical Point

近藤破坏量子临界点的电荷和自旋响应的动态缩放

• DOI: 10.1103/physrevlett.124.027205
• 发表时间: 2020
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Cai Ang;Yu Zuodong;Hu Haoyu;Kirchner Stefan;Si Qimiao
• 通讯作者: Si Qimiao

Bose-Fermi Anderson model with SU(2) symmetry: Continuous-time quantum Monte Carlo study

• DOI: 10.1103/physrevb.100.014439
• 发表时间: 2019-07-30
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Cai, Ang;Si, Qimiao
• 通讯作者: Si, Qimiao