Transport and Superconductivity in Strongly Correlated Quantum Matter

强相关量子物质中的输运和超导

• 批准号: 2111379
• 负责人: Philip Phillips
• 金额: $ 37.5万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2111379&HistoricalAwards=false
• 关键词: Transport; Superconductivity; Strongly; Correlated; Quantum

NONTECHNICAL SUMMARYThis award supports theoretical research aimed at understanding electronic and transport properties of systems in which strong interactions between electrons lead to emergent behavior such as high temperature superconductivity. In a superconductor, electrons conduct electricity without any loss, but this typically happens only at low temperatures. As electrical loss represents a significant portion of all electrical bills, a room temperature superconductor would represent a major advance in power transmission. The PI's work is focused on understanding a class of high-temperature superconductors discovered in 1987 that have defied understanding within the so-called BCS theory proposed in 1957 by Bardeen, Cooper, and Schrieffer. The primary difficulty is that while the BCS theory works fine for metals such aluminum where the interaction between the electrons can be ignored, this is not the case for the high-temperature superconductors where superconductivity occurs by doping materials which are insulators due to strong repulsion between electrons. The PI has advanced an exactly solvable model for such systems and shown how superconductivity emerges. Since the model is exactly solvable, a clear picture emerges as to how the BCS theory must be modified. The PI will work to quantify the differences and construct the universal features of superconductivity in these materials that have defied description in terms of the standard BCS theory.This award also supports training of graduate students seeking their PhD degrees in theoretical physics. The PI will be involved with other educational and outreach activities, such as continuing to revise his graduate textbook in theoretical solid state physics, serving on the Editorial Boards of prominent scientific journals, advancing initiatives within the American Physical Society at the intersection of physics and race, and working to increase diversity in the scientific workforce.TECHNICAL SUMMARYThis award supports theoretical research focused on new methods for the transport and superconducting properties of strongly correlated electron systems by using exactly solvable models, numerical calculations, and renormalization techniques to establish the existence of strongly coupled fixed points. The exactly solvable models allow new insight into the 35-year old problem of superconductivity in doped Mott insulators such as the high-temperature superconductors. The goal is to ascertain what new features emerge from Mott physics in the superconducting state. Another goal of the exactly solvable models is to determine if the physics they embody is governed by a new strongly coupled fixed point in much the same way Fermi liquid theory dictates the physics of simple metals. Success here could provide an organizing principle in the physics of strongly correlated electron matter. Finally, the focus on numerical calculations to determine the phase diagram of the dilute electron gas in the presence of a periodic potential is aimed at informing new experiments that have revealed novel insulating states that break translational symmetry in Moire bilayer systems.This award also supports training of graduate students seeking their PhD degrees in theoretical physics. The PI will be involved with other educational and outreach activities, such as continuing to revise his graduate textbook in theoretical solid state physics, serving on the Editorial Boards of prominent scientific journals, advancing initiatives within the American Physical Society at the intersection of physics and race, and working to increase diversity in the scientific workforce.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.

该奖项支持旨在理解系统的电子和输输性质的理论研究，其中电子之间的强相互作用导致诸如高温超导等紧急行为。在超导体中，电子可以毫无损耗地导电，但这通常只发生在低温下。由于电损耗占所有电费的很大一部分，室温超导体将代表着电力传输的重大进步。PI的工作重点是理解1987年发现的一类高温超导体，这类超导体在1957年由巴丁、库珀和施里弗提出的所谓BCS理论中是无法理解的。主要的困难是，虽然BCS理论适用于金属，如铝，电子之间的相互作用可以忽略不计，但这不是高温超导体的情况，超导性是通过掺杂材料产生的，这些材料是绝缘体，由于电子之间的强烈排斥。PI为这种系统提出了一个精确可解的模型，并展示了超导性是如何出现的。既然这个模型是完全可解的，那么关于如何修正BCS理论的清晰图景就出现了。PI将致力于量化这些材料的差异，并构建超导性的普遍特征，这些特征无法用标准BCS理论来描述。该奖项还支持培养攻读理论物理学博士学位的研究生。PI将参与其他教育和推广活动，例如继续修改理论固体物理学的研究生教科书，在著名科学期刊的编辑委员会任职，在物理学和种族的交叉领域推进美国物理学会的倡议，并努力增加科学劳动力的多样性。技术概述：该奖项支持的理论研究集中在强相关电子系统的输运和超导特性的新方法上，通过使用精确可解模型、数值计算和重整化技术来建立强耦合不动点的存在。精确可解的模型使人们对35年来掺杂莫特绝缘体（如高温超导体）的超导性问题有了新的认识。目标是确定超导状态下莫特物理中出现的新特征。精确可解模型的另一个目标是确定它们所体现的物理是否受到一个新的强耦合固定点的支配，就像费米液体理论支配简单金属的物理一样。这里的成功可以为强相关电子物质的物理学提供一个组织原则。最后，通过数值计算来确定存在周期势的稀电子气体的相图，旨在为揭示云纹双层系统中破坏平移对称性的新型绝缘状态的新实验提供信息。该奖项还支持培养攻读理论物理学博士学位的研究生。PI将参与其他教育和推广活动，例如继续修改理论固体物理学的研究生教科书，在著名科学期刊的编辑委员会任职，在物理学和种族的交叉领域推进美国物理学会的倡议，并努力增加科学劳动力的多样性。该奖项反映了美国国家科学基金会的法定使命，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

Thermodynamics of an exactly solvable model for superconductivity in a doped Mott insulator

掺杂莫特绝缘体中超导精确可解模型的热力学

• DOI: 10.1103/physrevb.105.184509
• 发表时间: 2022
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Zhao, Jinchao;Yeo, Luke;Huang, Edwin W.;Phillips, Philip W.
• 通讯作者: Phillips, Philip W.

Kitaev chain with a fractional twist

• DOI: 10.1103/physrevb.106.125109
• 发表时间: 2022-04
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Bora Basa;Gabriele La Nave;P. Phillips

Topological Mott insulator at quarter filling in the interacting Haldane model

• DOI: 10.1103/physrevresearch.5.013162
• 发表时间: 2022-07
• 期刊: Physical Review Research
• 影响因子: 4.2
• 作者: P. Mai;B. Feldman;P. Phillips

Correlated Hofstadter spectrum and flavour phase diagram in magic-angle twisted bilayer graphene

• DOI: 10.1038/s41567-022-01589-w
• 发表时间: 2021-07
• 期刊: Nature Physics
• 影响因子: 19.6
• 作者: Jiachen Yu;B. Foutty;Zhaoyu Han;M. Barber;Y. Schattner;Kenji Watanabe;T. Taniguchi;P. Phillips;Zhixuan Shen;S. Kivelson;B. Feldman

Probing the bulk plasmon continuum of layered materials through electron energy loss spectroscopy in a reflection geometry

• DOI: 10.1103/physrevb.106.155152
• 发表时间: 2022-03
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: C. Boyd;L. Yeo;P. Phillips