RUI: Investigation of Strongly Correlated Electron Behavior in Rare-Earth Related Materials

本项目支持少数民族本科院校稀土相关材料材料科学研究。主要的重点是超导和小间隙半导体稀土填充方角石化合物的合成和表征，目的是了解其潜在的机制。许多用途广泛的技术应用源于稀土材料的兴趣，例如，超导材料可用于节能和储能；量子磁体和拓扑绝缘体可用于高性能电子产品和量子计算机。在首席研究员实验室的研究允许本科生和硕士学位课程的学生直接参与实验凝聚态物理，让他们在学术生涯的早期阶段就有实践经验。本项目提供的研究和实习实践经验，不仅可以培养学生良好的基础知识、批判性思维、职业道德和解决问题的技能，成为独立的科学家，还可以鼓励学生在STEM（科学、技术、工程和数学）领域接受高等教育和职业生涯。技术摘要本项目支持稀土相关材料中强相关电子现象的实验研究。这些现象是由相互竞争的电子或磁性相互作用之间的微妙相互作用产生的。可以通过调节实验参数如温度、磁场、化学取代等进行控制。所研究的稀土化合物可以作为模型系统来探索电子态的局域性和流变性，并对现有的强相关电子物理理论进行检验。这些可以通过合成高质量的单晶和建立输运和热力学性质来实现。在稀土填充的skutterudite体系Pr1-xNdxOs4Sb12中，首席研究员（PI）的目标是通过钕取代的影响来理解pro4sb12中超导性的非常规性质。此外，根据PI最近发现的奇特的CeOs4Sb12的温度-磁场相图，它表明了一个价态转变和可能的多相。PI计划继续研究SmOs4Sb12， CeOs4Sb12， Ce1-xPrxOs4Sb12和Ce1-xNdxOs4Sb12的空穴掺杂化合物的电子行为，以研究这些体系中拓扑绝缘行为的潜力。最终，这些项目的结果可以帮助我们理解PrOs4Sb12的量子临界行为，无论它的超导性是否存在于与反铁磁或铁磁有序相关的量子临界点附近，还是其他诸如四极自由度之类的东西。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。

Non-Technical AbstractThis project supports materials science research of rare-earth related materials at a minority-serving undergraduate institution. The primary focus is on the synthesis and characterization of superconducting and small-gap semiconducting rare earth filled skutterudite compounds, with the goal of understanding their underlying mechanisms. Many versatile technical applications result from the rare-earth materials of interest, for examples, superconducting materials can be used for energy conservation and energy storage; quantum magnets and topological insulators can be used in high performance electronics and quantum computers. The research in the principal investigator's laboratory allows direct participation of undergraduate and master-degree-program students in the experimental condensed matter physics, giving them hands-on experience at the early stage of their academic life. The practical experience of research and placement provided by this project not only can train students to develop good fundamentals, critical thinking, work ethics, and troubleshooting skills to become independent scientists, but also encourage students to pursue higher education and careers in the fields of STEM (Science, Technology, Engineering, and Math).Technical AbstractThis project supports experimental research in the strongly correlated electron phenomena in rare-earth related materials. These phenomena arise from a subtle interplay between competing interactions, either electronic or magnetic. They can be controlled through tuning the experimental parameters such as temperature, magnetic field, chemical substitution. The rare-earth compounds under investigation can be used as model systems to probe the localized and the itinerant nature of the electron states and test the existing theories for strongly correlated electron physics. These can be achieved through the synthesis of high-quality single crystals and the establishment of transport and thermodynamic properties. In the rare-earth filled skutterudite systems Pr1-xNdxOs4Sb12, the principal investigator (PI) is aiming to understand the unconventional nature of the superconductivity in PrOs4Sb12 by the effect of neodymium substitution. Furthermore, in the light of the PI's recent discovery of the exotic temperature-magnetic-field phase diagram of CeOs4Sb12, it indicates a valence transition and possible multiple phases. The PI plans to continue in examining the electronic behavior of SmOs4Sb12, CeOs4Sb12, the hole doping compounds of Ce1-xPrxOs4Sb12 and Ce1-xNdxOs4Sb12 in order to investigate the potential of topological insulating behavior in these systems. Eventually, the results of the proposed projects can help us understand the quantum critical behavior in PrOs4Sb12 whether its superconductivity resides near a quantum critical point associated with antiferromagnetic or ferromagnetic ordering, or something else such as quadrupole degree of freedom.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.