Electronic and Magnetic Phenomena in Iron-based Superconductors

铁基超导体中的电子和磁现象

• 批准号: 1505826
• 负责人: Carmen Almasan
• 金额: $ 40万
• 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: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505826&HistoricalAwards=false
• 关键词: Electronic; Magnetic; Phenomena; Iron; based

Nontechnical description: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 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 mutual interplay between superconductivity and magnetism. They could also offer clues about other unconventional superconductors, such as the cuprates, and contribute to a more global understanding of the novel phenomenon of high temperature superconductivity. This highly interdisciplinary project allows graduate and undergraduate students, postdocs, and visitors 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 postdoc and graduate students. A female Ph.D. student participates in this project, hence, the project increases diversity within the field. The international collaborations with scientists in Romania and 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. She also addresses the professional development needs of science teachers in grades 6-10 by developing the physical science component of a new physical and life science graduate course. Finally, she provides middle school and high school physics teachers and their students workshops and lab tours. Technical description:This proposal addresses a major theme in condensed matter physics: unconventional superconductivity in Fe-based superconductors. The proposed research significantly enhances our fundamental understanding of charge conduction and magnetism of 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 novel electronic quantum states with real-space texture in iron pnictides/chalcogenites superconductors with either an antiferromagnetic Mott insulator or antiferromagnetic spin density wave parent compound; (2) reveal the microscopic coexistence of antiferromagnetism and superconductivity and its evolution with doping; (3) study quantum criticality in order to reveal possible quantum phase transitions induced by control parameters, elucidate the phase boundary between the paramagnetic and antiferromagnetic phases inside the superconducting state, and generate a phase diagram that provides direct evidence for a quantum critical line inside the superconducting phase; (4) study the symmetry of the superconducting gap in order to unambiguously distinguish between different pairing symmetries and reveal any universality in the doping dependence of the gap; (5) reveal the origin of the pseudogap region; (6) facilitate the training of highly qualified personnel through comprehensive and multifaceted research, improve STEM education through educator development at 6-10 grade levels, and perform outreach activities. The methods that are used in these studies are resistivity, magnetoresistivity, current-voltage, torque, and magnetization measurements. Understanding the intrinsic electronic, magnetic, and magnetotransport mechanisms in these complex materials may be a key component in understanding their unique and potentially useful physical properties. With iron pnictides/chalcogenites and cuprates to compare and contrast, the proposed research could contribute to finally uncovering the vital clues that theorists need to solve the mystery of high-temperature superconductivity. More broadly, the results from these basic investigations provide further understanding of the interplay between magnetism and superconductivity of other unconventional superconductors and insight into appropriate doping schemes to facilitate applications to electronic sensors and devices.

非技术描述：凝聚态物理的两个主要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，描述了由外部参数（如化学成分、压力或磁场）驱动的相互竞争的基态之间的相变。最近对非常规超导体的研究表明，超导性是在磁性有序相附近发展起来的。这提高了这些系统中量子相变的可能性，这些相变是由这些顺序的竞争类型引起的。目前对铁基超导体的研究主要集中在对铁基超导体的正常态性质和超导机理的认识上。这些研究增强了我们对量子相变控制这些超导体有限温度特性的程度的基本理解，并有望深入了解超导性和磁性之间的相互作用。它们还可以为其他非传统超导体，如铜酸盐，提供线索，并有助于对高温超导的新现象有更全面的了解。这个高度跨学科的项目允许研究生和本科生，博士后和访客从接触到多种实验技术，各种不同的物理系统和现象，以及凝聚态物理的前沿课题中受益。在当今以知识为基础、技术驱动的经济中，本研究项目参与者所获得的专业知识的多样性是一个巨大的优势，对未来在工业、政府或学术界的职业生涯有益。为博士后和研究生提供专业指导。一位女博士生参与了这个项目，因此，这个项目增加了该领域的多样性。与罗马尼亚和中国科学家的国际合作为国家的研究和教育基础设施做出了贡献。首席研究员为高级实验室开发教学实验室模块，通过实验验证量子力学中所学到的反直觉物理现象。她还通过开发新的物理和生命科学研究生课程的物理科学部分，解决了6-10年级科学教师的专业发展需求。最后，她还为中学和高中物理教师及其学生提供研讨会和实验室参观。技术描述：本提案解决了凝聚态物理中的一个主要主题：铁基超导体中的非常规超导性。本研究将大大提高我们对铁镍酸盐/硫原岩的电荷传导和磁性的基本认识，解决磁性与超导性相互作用的相关问题，并有助于对高温超导新现象的更全面的理解。本研究的目的是：(1)研究具有反铁磁Mott绝缘体或反铁磁自旋密度波母化合物的铁镍酸盐/硫原岩超导体中具有实空间织构的新型电子量子态；(2)揭示了反铁磁性和超导性的微观共存及其随掺杂的演变；(3)研究量子临界性，揭示控制参数可能引起的量子相变，阐明超导态内顺磁性相和反铁磁性相之间的相界，生成相图，为超导相内量子临界线的存在提供直接证据；(4)研究超导隙的对称性，以便明确区分不同的配对对称性，揭示隙中掺杂依赖性的普遍性；(5)揭示赝隙区成因；(6)通过全面和多方面的研究促进高素质人才的培养，通过6-10年级的教育工作者发展改善STEM教育，并开展外展活动。在这些研究中使用的方法是电阻率，磁电阻率，电流-电压，扭矩和磁化测量。了解这些复杂材料的内在电子、磁性和磁输运机制可能是理解其独特和潜在有用的物理性质的关键组成部分。有了铁镍酸盐/硫原岩和铜酸盐的比较和对比，这项提议的研究可能有助于最终揭示理论家解决高温超导之谜所需的重要线索。更广泛地说，这些基础研究的结果进一步了解了其他非常规超导体的磁性和超导性之间的相互作用，并深入了解了适当的掺杂方案，以促进电子传感器和设备的应用。

项目成果

Rapid suppression of the energy gap and the possibility of a gapless hidden order state in URu 2−x Re x Si 2

URu 2−x Re x Si 2 中能隙的快速抑制和无能隙隐序态的可能性

• DOI: 10.1080/14786435.2019.1600756
• 发表时间: 2019
• 期刊: Philosophical Magazine
• 影响因子: 1.6
• 作者: Ran, S.;Schmiedeshoff, G. M.;Pouse, N.;Jeon, I.;Butch, N. P.;Adhikari, R. B.;Almasan, C. C.;Maple, M. B.
• 通讯作者: Maple, M. B.

Temperature versus Sm concentration phase diagram and quantum criticality in the correlated electron system Ce1−xSmxCoIn5

相关电子系统 Ce1–xSmxCoIn5 中温度与 Sm 浓度的相图和量子临界性

• DOI: 10.1103/physrevb.97.235149
• 发表时间: 2018
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Pouse, N.;Jang, S.;White, B. D.;Ran, S.;Adhikari, R. B.;Almasan, C. C.;Maple, M. B.
• 通讯作者: Maple, M. B.

Short-range antiferromagnetic correlations in the superconducting state of filled skutterudite alloys Pr1−xEuxPt4Ge12

填充方钴矿合金 Pr1–xEuxPt4Ge12 超导状态下的短程反铁磁关联

• DOI: 10.1103/physrevb.98.064506
• 发表时间: 2018
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Adhikari, R. B.;Kunwar, D. L.;Jeon, I.;Maple, M. B.;Dzero, M.;Almasan, C. C.
• 通讯作者: Almasan, C. C.

Zero-field quantum critical point in Ce0.91Yb0.09CoIn5

Ce0.91Yb0.09CoIn5 中的零场量子临界点

• DOI: 10.1103/physrevb.97.184514
• 发表时间: 2018
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Singh, Y. P.;Adhikari, R. B.;Haney, D. J.;White, B. D.;Maple, M. B.;Dzero, M.;Almasan, C. C.
• 通讯作者: Almasan, C. C.

Orbital and Pauli limiting effects in heavily doped Ba0.05K0.95Fe2As2

重掺杂 Ba0.05K0.95Fe2As2 中的轨道和泡利限制效应

• DOI: 10.1103/physrevb.92.174524
• 发表时间: 2015
• 期刊: Physical Review B
• 影响因子: 3.7