CAREER: Discovering and Understanding Layered Nickelate Superconductors

该奖项支持综合研究、推广和教育工作，以促进对超导材料的基本理解。超导是一种物质的量子态，电子在材料中移动时没有电阻，也就是说，不会因为加热而损失任何能量。超导材料对不同的技术至关重要：从磁共振成像仪到高能物理加速器，再到磁悬浮列车。然而，它们的用途往往受到超导体通常出现的低得令人望而却步的温度的限制。提高这种转变温度和发现新的超导体一直受到限制，因为在某些类别的材料中，对导致超导性的原因缺乏共识。其中一类是铜氧化物，它在20世纪80年代的发现对物理学产生了深远的影响，因为它们可以在比当时已知的任何材料更高的温度下超导。该项目将使用先进的计算和理论方法来研究镍氧化物-基于元素周期表中镍与铜的接近性的有前途的超导候选材料。该项目的目标是发现一个新的镍基超导体家族，同时为高温超导的起源提供见解。该团队将开发适用于超导材料的计算方法，并对电子进行模拟，以确定镍和铜氧化物物理特性之间的异同。第一族镍基超导体的发现将开辟新的领域，并建立产生超导性的相关参数。这是提高超导性产生温度的必要因素，并为创造新型超导材料提供了途径。研究活动与教育和推广计划相结合，将超导和物理计算建模带给凤凰城的学生和公众。该计划的重点是通过为拉丁裔社区的高中女生举办外展日，以及为低收入地区的学生举办一系列计算机夏季讲习班，为来自服务欠缺地区的高中生提供指导。这些活动的更广泛影响将是让有才华的年轻学生更早地接触到研究，这些学生通常在他们的社区中看不到科学职业道路。PI还将为开放活动开发演示，以教育和吸引公众对超导材料的认识。最后，该奖项将通过招募和建议本科生和研究生参与凝聚态物理和材料研究，为形成未来的科学和技术劳动力做出贡献。该奖项支持综合研究、推广和教育工作，以促进对超导材料的基本理解。在被发现一个多世纪后，超导性仍然是凝聚态物理研究中最活跃的领域之一。在上世纪80年代末对铜酸盐进行密集勘探之后，2006年铁基超导体的发现使该领域重新焕发了活力。然而，确定高温超导的机制和确定为什么高温超导材料的特性如此特殊是尚未回答的基本问题。解决这些问题的多种方法之一是寻找合适的模拟材料。在这种情况下，定位镍酸盐是一个明显的策略，因为镍和铜在元素周期表中彼此相邻。本项目将发展理论和计算方法来研究层状氧化镍材料的超导性。所提出的研究的明确目标是发现和建立镍酸盐超导体第一族的理论基础，同时以微观方式解决它们的行为。理论方法将从快速密度泛函理论到计算密集的准粒子自洽GW+动态平均场理论计算。利用这种方法，该团队将确定层状镍酸盐相图的复杂性，其中竞争相与超导性之间的关系，并最终为高温超导性的性质和起源提供新的见解。与超导铜酸盐的系统比较，将为确定产生高温超导的相关参数奠定基础，并为创造新型超导材料开辟道路。与研究工作相结合，PI将建立一个教育和推广计划，通过i)为低收入地区的高中生举办计算夏季研讨会，ii)为拉丁裔社区的高中女生举办推广日，以及iii)以超导为中心的开放日活动，向凤凰城的学生和公众介绍超导和物理计算建模。这些拓展和教育工作将使亚利桑那州立大学所服务的社区直接受益，因为它使各行各业的人们接触到科学，并影响到通常在他们的社区中看不到科学职业道路的年轻一代。最后，该奖项将通过招募本科生和研究生参与凝聚态物理研究，为形成未来的科学和技术劳动力做出贡献。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。

NONTECHNICAL SUMMARYThis award supports an integrated research, outreach, and educational effort to advance the fundamental understanding of superconducting materials. Superconductivity is a quantum state of matter whereby electrons move through a material without resistance, namely, without losing any energy to heat. Superconducting materials are of paramount importance to different technologies: from magnetic resonance imaging machines to accelerators for high-energy physics, and magnetic levitating trains. However, their usefulness is often restricted by the prohibitively low temperatures at which superconductivity usually emerges. Increasing this transition temperature and discovering new superconductors has been limited by the lack of consensus as to what causes superconductivity in some classes of materials. One of these classes is represented by copper oxides whose discovery in the 1980s had a profound influence on physics as they could superconduct at a higher temperature than any material known at the time. This project will use advanced computational and theoretical methods to investigate nickel oxides - promising candidate materials for superconductivity based on the proximity of nickel to copper in the periodic table. The goal of the project is to discover a new family of nickel-based superconductors while providing insights into the origin of high-temperature superconductivity. The team will develop computational approaches suited for superconducting materials and perform simulations of electrons to establish the differences and similarities between the physics of nickel and copper oxides. The discovery of the first family of nickel oxide-based superconductors will open new venues and establish the relevant parameters that give rise to superconductivity. This is a necessary ingredient to enhance the temperatures at which superconductivity emerges and to provide routes to create novel superconducting materials. The research activities are integrated with an educational and outreach program to bring superconductivity and computational modeling in physics to students and to the general public in metro Phoenix. The program has an emphasis on mentoring high-school students from underserved areas via an outreach day for high-school girls in majority-Latino neighborhoods, and through a series of computational summer workshops for students from low-income areas. The broader impact of these activities will be early exposure to research for young talented students who generally do not see science career paths represented in their communities. The PI will also develop demos for open house events to educate and engage the general public on superconducting materials. Finally, this award will contribute to forming tomorrow's scientific and technological workforce by recruiting and advising undergraduate and graduate students to participate in condensed matter physics and materials research. TECHNICAL SUMMARY This award supports an integrated research, outreach, and educational effort to advance the fundamental understanding of superconducting materials. More than a century after its discovery, superconductivity remains one of the most active areas of condensed matter physics research. The discovery of iron-based superconductors in 2006 reinvigorated the field after an intensive exploration of cuprates from the late 1980s. However, pinpointing the mechanism of high-temperature superconductivity and determining why the characteristics of high-temperature superconducting materials are so special are fundamental questions yet to be answered. Among the multiple approaches to addressing these questions has been the search for cuprate analog materials. In this context, targeting nickelates is an obvious strategy since nickel and copper are next to each other in the periodic table. This project will develop theoretical and computational approaches to investigate superconductivity in layered nickel oxide materials. The explicit goal of the proposed research is to discover and establish the theoretical foundations of the first family of nickelate superconductors while addressing their behavior in a microscopic way. The theory approach will run the gamut from fast density functional theory to computationally intensive quasiparticle-self consistent GW+dynamical mean-field theory calculations. With this methodology, the team will determine the complexity of the layered nickelate phase diagram, the relationship between competing phases therein and superconductivity, and ultimately provide new insights into the nature and origin of high temperature superconductivity. The systematic comparison with superconducting cuprates will lay the foundation of the relevant parameters that give rise to high-temperature superconductivity and establish routes to create novel superconducting materials. Integrated with the research efforts, the PI will establish an educational and outreach program to bring superconductivity and computational modeling in physics to students and to the general public in metro Phoenix through i) a computational summer workshop for high school students from low-income areas, ii) an outreach day for high school girls in majority-Latino neighborhoods, and iii) open house events centered around superconductivity. These outreach and educational efforts will directly benefit the community Arizona State University serves by exposing a wide cross-section of people to science and by influencing younger generations that generally do not see science career paths represented in their communities. Finally, this award will contribute to forming tomorrow's scientific and technological workforce by recruiting undergraduate and graduate students to participate in condensed matter physics 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.