Nematic Enhancement of Superconductivity

超导性的向列增强

• 批准号: 2303090
• 负责人: Johnpierre Paglione
• 金额: $ 70.24万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303090&HistoricalAwards=false
• 关键词: Nematic; Enhancement; Superconductivity

Non-technical Abstract: The unprecedentedly high transition temperatures in iron- and copper-based superconductors remain as one of the most important unsolved problems in condensed matter physics, and understanding the complex normal state of these compounds has become a major physics challenge in its own right, one that sits at the core of our quest to understand strongly correlated electron systems. But the appearance in the vicinity of superconductivity of so-called electronic nematic phases, where the electrons in a material exhibit a spontaneous preferred orientation, drives the need to better understand this degree of freedom in a generic manner. This project studies the details of this relationship in a model system, providing an important next step in elucidating the potential for enhancing superconducting pairing via nematic fluctuations and understanding the role of electronic nematicity in condensed matter. Technical Abstract: Understanding 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 where other complicating factors, commonly long range magnetic order, make the impacts of the nematic phase challenging to isolate. This program investigates a nematically enhanced superconductor free of magnetism, namely the nickel-pnictide solid solution series Ba1 xSrxNi2As2, which has been shown to exhibit novel structural, charge and electronic nematic orders that are highly tunable by chemical substitution. The project involves transport, spectroscopic and thermodynamic measurements of the superconducting gap dependence on strain, evaluation of symmetries and band structure using thermal transport and photoemission, and the interaction between charge order and superconductivity to 1) further build the connection between nematicity and superconductivity, and 2) better understand the relationship between nematicity and charge order. The broader impact of this program involves undergraduate students, graduate students, 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 program also interfaces with the University of Maryland’s annual Fundamentals of Quantum Materials Winter School, which focuses on training the next generation of scientists pursuing careers in quantum materials research.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：铁基和铜基超导体前所未有的高转变温度仍然是凝聚态物理学中最重要的未解决问题之一，理解这些化合物的复杂正常状态本身已经成为一个重大的物理挑战，这是我们寻求理解强相关电子系统的核心。但是，在超导性附近出现所谓的电子取向相，即材料中的电子表现出自发的择优取向，这就需要以一般的方式更好地理解这种自由度。该项目研究了模型系统中这种关系的细节，为阐明通过电子涨落增强超导配对的潜力和理解凝聚态中电子向列性的作用提供了重要的下一步。 技术摘要：了解向列性及其对超导性的影响，受到缺乏表现出电子相的材料的限制。这些材料主要限于某些高Tc超导体和少数其他复杂材料，其中其他复杂因素，通常是长程磁序，使得超导相的影响难以隔离。该计划研究了一种向列增强的无磁性超导体，即镍-磷属元素化物固溶体系列Ba 1 xSrxNi 2As 2，它已被证明具有新颖的结构，电荷和电子的有序性，这些有序性通过化学取代高度可调。该项目涉及超导能隙对应变依赖性的传输、光谱和热力学测量，使用热传输和光电发射评估对称性和能带结构，以及电荷有序和超导性之间的相互作用，以1）进一步建立向列性和超导性之间的联系，2）更好地理解向列性和电荷有序之间的关系。 该计划的更广泛影响涉及跨学科研究和具有科学技术意义的领域的本科生、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，并包括参与与马里兰州天文学和物理学（GRADMAP）计划的研究生资源推进多样性。该计划还与马里兰州的量子材料冬季学校的年度基础的大学接口，其重点是培养追求量子材料研究的职业生涯的下一代科学家。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。