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

非技术摘要本项目支持在少数民族服务的本科院校的稀土相关材料的材料科学研究。 主要的重点是超导和小间隙半导体稀土填充方钴矿化合物的合成和表征，以了解其潜在的机制的目标。 令人感兴趣的稀土材料可以带来许多通用的技术应用，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。 主要研究者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学，让他们在学术生涯的早期阶段获得实践经验。 该项目提供的研究和实习实践经验不仅可以培养学生发展良好的基础知识、批判性思维、职业道德和故障排除技能，成为独立的科学家，还可以鼓励学生在STEM领域接受高等教育和职业生涯（科学、技术、工程、技术摘要本项目支持稀土相关材料中强关联电子现象的实验研究。 这些现象产生于电子或磁性相互作用之间的微妙相互作用。 可以通过调节实验参数如温度、磁场、化学取代来控制它们。 所研究的稀土化合物可以作为模型系统来探测电子态的定域和巡游性质，并检验现有的强关联电子物理理论。 这些可以通过合成高质量的单晶和建立传输和热力学性质来实现。 在稀土填充的方钴矿系统Pr 1-xNdxOs 4Sb 12中，首席研究员（PI）的目标是通过钕替代的效果来理解PrOs 4Sb 12中超导性的非常规性质。 此外，根据PI最近发现的CeOs 4Sb 12的奇异温度-磁场相图，它表明了价态转变和可能的多相。 PI计划继续研究SmOs 4Sb 12，CeOs 4Sb 12，Ce 1-xPrxOs 4Sb 12和Ce 1-xNdxOs 4Sb 12空穴掺杂化合物的电子行为，以研究这些系统中拓扑绝缘行为的潜力。最终，所提出的项目的结果可以帮助我们理解PrOs 4Sb 12的量子临界行为，无论其超导性是否位于与反铁磁或铁磁有序相关的量子临界点附近，该奖项反映了NSF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进行评估，被认为值得支持审查标准。

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.