Electronic and Magnetic Phenomena in Heavy-Fermion and Iron-Based Superconductors

重费米子和铁基超导体中的电子和磁性现象

• 批准号: 1904315
• 负责人: Carmen Almasan
• 金额: $ 46.91万
• 依托单位: Kent State 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: 2019-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1904315&HistoricalAwards=false
• 关键词: Electronic; Magnetic; Phenomena; Heavy; Fermion

Non-Technical Abstract:Two major themes in condensed matter physics are quantum critical phenomena and unconventional superconductivity. A quantum phase transition takes place at zero temperature and describes a phase transition between competing ground states driven by an external parameter such as chemical composition, pressure, or magnetic field. The recent studies of unconventional superconductors show that superconductivity develops in proximity to a magnetically ordered phase. This raises the possibility of quantum phase transitions in these systems arising from competing types of such orders. The present studies of unconventional superconductors such as heavy fermions and iron-based superconductors mainly focus on the understanding of the normal state properties of these superconductors and on the mechanism of superconductivity. These studies enhance our fundamental understanding of the extent to which a quantum phase transition controls the finite temperature properties of these superconductors and promise insight into the interplay between magnetism and superconductivity of other unconventional superconductors. This new knowledge could provide a more global understanding of the phenomenon of unconventional SC. This highly interdisciplinary project allows graduate and undergraduate students to benefit from exposure to a diversity of experimental techniques, a variety of different physical systems and phenomena, and forefront topics in condensed matter physics. The diversity of the expertise gained by the participants in this research program is a substantial advantage in today's knowledge based, technology driven economy, being beneficial to a future career in industry, government, or academia. Professional mentoring is provided for the graduate students. The international collaborations with scientists in China contribute to the nation's infrastructure for research and education. The principal investigator develops teaching lab modules for a senior laboratory that verifies experimentally counterintuitive physical phenomena learned in Quantum Mechanics; e.g., how a single photon will interfere with itself, or how local realism can be violated. She also participates in the STEM education of K-12 students by contributing to several activities: Annual STEM Project Fair, Science Experience Internship, and Young Women's Summer Institute. In addition, she provides middle school and high school students and their physics teachers workshops and lab tours. Technical Abstract:This proposal addresses a major theme in condensed matter physics: quantum critical phenomena in heavy fermions and iron-based superconductors. The proposed research significantly enhances our fundamental understanding of charge conduction and magnetism of heavy fermions and iron pnictides/chalcogenites, addresses issues related with the interplay between magnetism and superconductivity, and contributes to a more global understanding of the novel phenomenon of high temperature superconductivity. The goals of this research are to: (1) study coexistence of antiferromagnetism and superconductivity; (2) reveal quantum phase transitions; (3) study nature of quantum critical points; (4) study pseudogap region and search for nematic states; (5) facilitate the training of highly qualified personnel through comprehensive and multifaceted research and improve K-12 STEM education. The methods that are used in these studies are resistivity, magnetoresistivity, current-voltage, torque, thermoelectric power, and magnetization measurements. The proposed research will significantly enhance our fundamental understanding of quantum critical phenomena, arising from competing types of orders, in iron-based and heavy-fermion superconductors. Specifically, it will address issues related with the interplay between magnetism and superconductivity, and reveal the nature of the ground state, for example a conventional metal or an ordered phase, which would have appeared had superconductivity not intervened. Fundamentally, it will reveal the extent to which quantum criticality controls the finite temperature properties of these systems. This research could also contribute to a more global understanding of the novel phenomenon of unconventional superconductivity. Understanding the intrinsic electronic, magnetic, and magnetotransport mechanisms in these complex materials is critical to understanding the nature of strongly correlated materials and revealing the origin of unconventional superconductivity.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：凝聚态物理学的两大主题是量子临界现象和非常规超导性。量子相变发生在零温度下，描述了由化学成分、压力或磁场等外部参数驱动的竞争基态之间的相变。最近对非常规超导体的研究表明，超导性在磁有序相附近发展。这就提出了这些系统中量子相变的可能性，这些相变是由这些秩序的竞争类型引起的。目前对非常规超导体如重费米子和铁基超导体的研究主要集中在对这些超导体正常态性质的理解和对超导电性机制的研究上。这些研究增强了我们对量子相变控制这些超导体的有限温度特性的程度的基本理解，并有望深入了解其他非常规超导体的磁性和超导性之间的相互作用。这种新的知识可以提供一个非常规SC现象的更全面的理解。这个高度跨学科的项目使研究生和本科生能够受益于接触到各种实验技术，各种不同的物理系统和现象，以及凝聚态物理学的前沿课题。参与者在这项研究计划中获得的专业知识的多样性是当今以知识为基础，技术驱动的经济中的一个重大优势，有利于未来在工业，政府或学术界的职业生涯。为研究生提供专业指导。与中国科学家的国际合作有助于国家的研究和教育基础设施。首席研究员为高级实验室开发教学实验模块，该实验室通过实验验证量子力学中学到的违反直觉的物理现象;例如，单个光子如何干扰自身，或者如何破坏局部真实性。她还通过参与几项活动参与K-12学生的STEM教育：年度STEM项目博览会，科学体验实习和年轻女性暑期学院。此外，她还为初中和高中学生及其物理教师提供研讨会和实验室图尔斯之旅。技术摘要：该提案涉及凝聚态物理学的一个主要主题：重费米子和铁基超导体中的量子临界现象。拟议的研究大大提高了我们对重费米子和铁磷属元素化物/硫属元素化物的电荷传导和磁性的基本理解，解决了与磁性和超导性之间相互作用相关的问题，并有助于对高温超导性的新现象进行更全面的理解。本研究的目标是：（1）研究反铁磁性和超导性的共存;（2）揭示量子相变;（3）研究量子临界点的性质;（4）研究赝能隙区和寻找量子态;（5）通过全面和多方面的研究促进高素质人才的培养，并改善K-12 STEM教育。在这些研究中使用的方法是电阻率，磁阻，电流-电压，扭矩，热电功率和磁化测量。拟议的研究将显着提高我们的量子临界现象的基本理解，从竞争类型的订单，在铁基和重费米子超导体。具体来说，它将解决与磁性和超导性之间的相互作用有关的问题，并揭示基态的性质，例如常规金属或有序相，如果没有超导性的干预，就会出现。从根本上讲，它将揭示量子临界性控制这些系统的有限温度特性的程度。这项研究也有助于全球对非常规超导现象的理解。理解这些复杂材料中的内在电子、磁性和磁输运机制对于理解强关联材料的性质和揭示非常规超导性的起源至关重要。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

Heat capacity of URu2−xOsxSi2 at low temperatures

URu2·xOsxSi2 的低温热容

• DOI: 10.1103/physrevb.105.l041106
• 发表时间: 2022
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Kunwar, D. L.;Panday, S. R.;Deng, Y.;Ran, S.;Baumbach, R. E.;Maple, M. B.;Almasan, Carmen C.;Dzero, M.
• 通讯作者: Dzero, M.

Quantum criticality in Ce1−xSmxCoIn5

Ce1–xSmxCoIn5 中的量子临界性

• DOI: 10.1103/physrevb.103.224519
• 发表时间: 2021
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Kunwar, D. L.;Adhikari, R. B.;Pouse, N.;Maple, M. B.;Dzero, M.;Almasan, C. C.
• 通讯作者: Almasan, C. C.

Vanishing RKKY interactions in Ce-based cage compounds

Ce基笼状化合物中RKKY相互作用的消失

• DOI: 10.1088/1361-648x/acf019
• 发表时间: 2023
• 期刊: Journal of Physics: Condensed Matter
• 作者: Konic, A. M.;Zhu, Y.;Breindel, A. J.;Deng, Y.;Moir, C. M.;Maple, M. B.;Almasan, C. C.;Dzero, M.
• 通讯作者: Dzero, M.

Evolution of non-Kramers doublets in magnetic field in PrNi2Cd20 and PrPd2Cd20

PrNi2Cd20 和 PrPd2Cd20 中非克莱默双峰在磁场中的演化

• DOI: 10.1103/physrevb.104.205139
• 发表时间: 2021
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Konic, A. M.;Adhikari, R. B.;Kunwar, D. L.;Kirmani, A. A.;Breindel, A.;Sheng, R.;Maple, M. B.;Dzero, M.;Almasan, C. C.
• 通讯作者: Almasan, C. C.