NMR Studies of Nematicity in Strongly Correlated Electron Systems under Uniaxial Strain

单轴应变下强相关电子系统向列性的核磁共振研究

• 批准号: 1807889
• 负责人: Nicholas Curro
• 金额: $ 40.17万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1807889&HistoricalAwards=false
• 关键词: NMR; Studies; Nematicity; Strongly; Correlated

Nontechnical Abstract: In high temperature superconductors an electronic state with zero resistance emerges at low temperatures. Superconductivity is a quantum mechanical phenomenon that has a wide range of potential applications, including magnetic levitation and energy transport without dissipation, capable of changing the society and economy in a transformative way. But superconductivity is still poorly understood and is seen in various types of materials. A particularly interesting case occurs for nematic materials, in which the electronic behavior spontaneously becomes anisotropic. This behavior can be induced in the laboratory by applying strain to the crystal, which may alter its physical properties. We aim to investigate the microscopic behavior using magnetic resonance to study the electronic response to strain. This project will support the education of undergraduate and graduate students, as well as a broad audience of senior citizens via a new course on quantum mechanics without equations for the public through the university extension office. Technical Abstract: The objective of this project is to develop a fundamental understanding of quantum critical nematic fluctuations in strongly correlated electron materials. Electronic nematic order has been observed in the iron and cuprate superconductors, and evidence suggests that nematic fluctuations may be responsible for the superconducting pairing mechanism and the non-Fermi liquid behavior at optimal doping in these materials. However, the presence of multiple types of order parameters and their fluctuations complicate the interpretation of experiments and preclude the identification of the essential physics behind these phenomena. Recent evidence suggests that electronic nematic fluctuations may be responsible for superconductivity in some cases. However, multiple types of electronic order parameters can be present simultaneously, and by their very nature strongly correlated systems are highly sensitive to impurities, giving rise to microscopic inhomogeneity that obfuscates experimental observations. As a result, there is no clear picture as to what extent electron nematicity is central to the fundamental physics of high temperature superconductivity in the iron and cuprates materials, or whether it is simply a curious epiphenomenon. This project will answer this question through nuclear magnetic resonance studies of cuprates, vanadates, iridates and iron pnictide materials under uniaxial strain in regimes of phase space that have never been investigated. These investigations will disentangle the roles of disorder, nematicity, and antiferromagnetism at play in the normal state of the high temperature iron and cuprate superconductors, and will also explore new regimes of phase space using uniaxial strain as a thermodynamic tuning variable. The outcome of this project will be a more complete understanding of the role of quantum critical nematic fluctuations and the essential physics of strongly correlated electron materials.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.

非技术摘要：在高温超导体中，在低温下出现零电阻电子态。超导是一种量子力学现象，具有广泛的潜在应用前景，包括磁悬浮和无耗散的能量传输，能够以一种变革性的方式改变社会和经济。但超导性仍然知之甚少，在各种类型的材料中都能看到。一种特别有趣的情况发生在向列型材料中，其中电子行为自发地变成各向异性。这一行为可以在实验室中通过对晶体施加应变来诱导，这可能会改变其物理性质。我们的目标是通过磁共振研究应变的电子响应来研究其微观行为。该项目将通过大学推广办公室为公众开设一门新的不含方程的量子力学课程，支持本科生和研究生以及广大老年人的教育。技术摘要：本项目的目标是对强关联电子材料中的量子临界向列相涨落有一个基本的了解。在铁和铜酸盐超导体中观察到了电子向列相秩序，证据表明向列相涨落可能是超导配对机制和在这些材料中最佳掺杂时的非费米液体行为的原因。然而，多种序参数及其涨落的存在使实验的解释变得复杂，并排除了识别这些现象背后的基本物理的可能性。最近的证据表明，在某些情况下，电子向列相涨落可能是超导电性的原因。然而，多种类型的电子有序参数可以同时存在，而且从本质上讲，强关联系统对杂质高度敏感，导致微观不均匀，混淆了实验观察。因此，对于电子向列性在多大程度上是铁和铜酸盐材料高温超导的基本物理核心，或者它是否只是一种奇怪的附带现象，目前还没有明确的图景。这个项目将通过对单轴应变下的铜酸盐、钒酸盐、霓虹酸盐和铁磷酸盐材料的核磁共振研究来回答这个问题，这些材料的相空间范围从未被研究过。这些研究将揭开无序、向列性和反铁磁性在高温铁和铜酸盐超导体正常态中的作用，并将探索以单轴应变为热力学调谐变量的新的相空间区域。该项目的成果将是更全面地理解量子临界向列相涨落的作用和强关联电子材料的基本物理。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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

Hyperfine couplings as a probe of orbital anisotropy in heavy-fermion materials

• DOI: 10.1103/physrevb.104.035154
• 发表时间: 2020-10
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: P. Menegasso;J. Souza;I. Vinograd;Z. Wang;S. Edwards;P. Pagliuso;N. Curro;R. Urbano

Coherence temperature in the diluted periodic Anderson model

• DOI: 10.1103/physrevb.99.195116
• 发表时间: 2018-12
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: N. Costa;T. Mendes-Santos;T. Paiva;N. Curro;R. R. D. Santos-R.;R. Scalettar

Site-specific Knight shift measurements of the dilute Kondo lattice system Ce1−xLaxCoIn5

• DOI: 10.1103/physrevb.99.165106
• 发表时间: 2019-01
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: M. Lawson;Blaine Bush;A. Shockley;C. Capan;Z. Fisk;N. Curro

Anisotropic nematic fluctuations above the ferroquadrupolar transition in TmVO4

TmVO4 铁四极转变之上的各向异性向列涨落

• DOI: 10.1103/physrevb.104.205137
• 发表时间: 2021
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Wang, Z.;Vinograd, I.;Mei, Z.;Menegasso, P.;Garcia, D.;Massat, P.;Fisher, I. R.;Curro, N. J.
• 通讯作者: Curro, N. J.

Nematicity and Glassy Behavior Probed by Nuclear Magnetic Resonance in Iron-Based Superconductors

• DOI: 10.3389/fphy.2022.877628
• 发表时间: 2022-04
• 作者: N. Curro;T. Kissikov;M. Tanatar;R. Prozorov;S. Bud’ko;P. Canfield