Nematic Enhancement of Superconductivity

超导性的向列增强

• 批准号: 1905891
• 负责人: Johnpierre Paglione
• 金额: $ 45万
• 依托单位: University of Maryland, College Park
• 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: 2019-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905891&HistoricalAwards=false
• 关键词: Nematic; Enhancement; Superconductivity

Nontechnical abstract:Nematicity, which has been a central theme in the study of iron-based superconductors, is a term borrowed from the field of liquid crystals, where it refers to a phase with broken rotational but preserved translational symmetry. High temperature superconductivity in copper-oxide and iron-pnictide materials continues to fascinate and stimulate the scientific community due to the unanswered questions about the mechanism behind Cooper pairing of electrons to produce record-high transition temperatures. These factors demand not only continued investigation and characterization of known nematic systems but an additional, targeted research effort to uncover and understand other nematic systems and its potential applications within material physics. However, understanding electronic nematicity, and its impact on superconductivity, is limited by the dearth of materials demonstrated to exhibit an electronic nematic phase. These materials are mostly limited to certain high-Tc superconductors and a small handful of other complex materials. In this project, a series of experiments probing both the nematic response and the superconducting state properties of nematically active materials are performed to help understand the influence of nematic fluctuations on superconductivity, and hence elucidate the role of nematicity in enhancing transition temperatures in both iron- and copper-based high-Tc superconductors. This project involves undergraduate, graduate and postdoctoral scientists in interdisciplinary research and areas of scientific and technological significance, including collaborative and exchange programs with external institutions, and includes participation in the Graduate Resources Advancing Diversity with Maryland Astronomy and Physics (GRADMAP) program, the Fundamentals of Quantum Materials Winter School, and the NIST Summer Undergraduate Research Fellowships (SURF) Program.Technical abstract:Electronically driven nematicity has taken on an increased significance as a widely observed phase in the larger electronic phase diagrams of both copper- and iron-based high-temperature superconductor systems. As a generic feature of many iron and cuprate superconductors, understanding electronic nematicity, particularly as it relates to these specific compounds, is essential to truly understanding the conditions from which high Tc emerges. However, in these systems other complicating factors, commonly long range magnetic order, make the impacts of the nematic phase challenging to isolate. This project investigates the BaNi2As2 nickel-pnictide system, a newly discovered nematically enhanced superconductor series that is free of magnetism. Transport and thermodynamic measurements as well as scattering experiments are being employed to characterize both the electronic nematic properties as well as the nature of the superconducting state as the electronic system is tuned by chemical pressure, doping and applied strain. With a growing body of theoretical work suggesting that nematicity may in fact interact cooperatively with Cooper pairing, understanding this correlated electronic phase and how it relates to pairing is thus crucial to understanding and advancing high-Tc 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：向列性一直是铁基超导体研究的中心主题，它是从液晶领域借用的一个术语，指的是旋转对称性破坏但平移对称性保持不变的相。氧化铜和铁镍基材料的高温超导性继续吸引和刺激着科学界，因为关于电子库珀配对产生创纪录的高转变温度背后的机制尚未解决的问题。这些因素不仅需要继续研究和表征已知的向列系统，还需要额外的、有针对性的研究工作，以发现和理解其他向列系统及其在材料物理学中的潜在应用。然而，了解电子向列相及其对超导性的影响，由于缺乏证明具有电子向列相的材料而受到限制。这些材料大多局限于某些高温超导体和少数其他复杂材料。在这个项目中，进行了一系列实验，探测向列反应和向列活性材料的超导状态特性，以帮助理解向列波动对超导性的影响，从而阐明向列性在提高铁基和铜基高tc超导体转变温度中的作用。该项目涉及跨学科研究和科学技术意义领域的本科生，研究生和博士后科学家，包括与外部机构的合作和交流计划，并包括参与马里兰天文学和物理学研究生资源推进多样性（GRADMAP）计划，量子材料基础冬季学校和NIST夏季本科生研究奖学金（SURF）计划。技术摘要：在铜基和铁基高温超导体系统的较大电子相图中，电子驱动向列性作为一种广泛观察到的相，具有越来越重要的意义。作为许多铁和铜超导体的普遍特征，理解电子向列性，特别是与这些特定化合物相关的电子向列性，对于真正理解高Tc产生的条件至关重要。然而，在这些系统中，其他复杂因素，通常是长距离磁序，使得向列相的影响难以隔离。本项目研究了BaNi2As2镍镍系，这是一种新发现的无磁性向列增强超导体系列。传输和热力学测量以及散射实验被用来表征电子向列性质以及超导状态的性质，因为电子系统是由化学压力、掺杂和施加应变调谐的。随着越来越多的理论工作表明向列性实际上可能与库珀配对相互作用，理解这种相关的电子相及其与配对的关系对于理解和推进高tc超导性至关重要。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

Absence of precursor incommensurate charge order in electronic nematic Ba0.35Sr0.65Ni2As2

电子向列相 Ba0.35Sr0.65Ni2As2 中不存在前体不相称的电荷顺序

• DOI: 10.1103/physrevb.106.054107
• 发表时间: 2022
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Collini, John;Lee, Sangjun;Sun, Stella X.-L.;Eckberg, Chris;Campbell, Daniel J.;Abbamonte, Peter;Paglione, Johnpierre
• 通讯作者: Paglione, Johnpierre

Pressure-induced suppression of ferromagnetism in the itinerant ferromagnet LaCrSb3

压力诱导的巡回铁磁体 LaCrSb3 中铁磁性的抑制

• DOI: 10.1103/physrevb.101.214408
• 发表时间: 2020
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Brubaker, Z. E.;Harvey, J. S.;Badger, J. R.;Ullah, R. R.;Campbell, D. J.;Xiao, Y.;Chow, P.;Kenney-Benson, C.;Smith, J. S.;Reynolds, C.
• 通讯作者: Reynolds, C.

Sixfold enhancement of superconductivity in a tunable electronic nematic system

• DOI: 10.1038/s41567-019-0736-9
• 发表时间: 2020
• 期刊: Nature physics
• 影响因子: 19.6
• 作者: Eckberg C;Campbell DJ;Metz T;Collini J;Hodovanets H;Drye T;Zavalij P;Christensen MH;Fernandes RM;Lee S;Abbamonte P;Lynn JW;Paglione J
• 通讯作者: Paglione J