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

非技术摘要该项目支持少数民族服务本科院校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的Skutterudite化合物的合成和表征，目的是了解其潜在的机制。许多广泛的技术应用源于感兴趣的稀土材料，例如超导材料可以用于节能和储能；量子磁铁和拓扑绝缘体可以用于高性能电子和量子计算机。首席研究员实验室的研究允许本科生和硕士研究生直接参与实验凝聚态物理，让他们在学术生活的早期阶段获得实践经验。该项目提供的研究和安置的实践经验不仅可以培养学生成为独立科学家的良好基础、批判性思维、职业道德和故障排除技能，还可以鼓励学生在STEM(科学、技术、工程和数学)领域追求高等教育和职业生涯。技术摘要该项目支持稀土相关材料中强相关电子现象的实验研究。这些现象源于相互竞争的电子或磁性相互作用之间的微妙相互作用。通过调节温度、磁场、化学取代度等实验参数，可以对它们进行控制。所研究的稀土化合物可以作为模型系统来探索电子态的定域性和巡回性，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以及建立输运和热力学性质来实现。在稀土掺杂的Skutterudite Pr1-xNdxOs4Sb12体系中，首席研究员(PI)的目标是了解PrOs4Sb12超导电性的非常规性质。此外，根据PI最近发现的CeOs4Sb12的奇异温度-磁场相图，它表明存在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，以研究这些系统中拓扑绝缘行为的潜力。最终，拟议项目的结果可以帮助我们理解PrOs4Sb12中的量子临界行为，无论它的超导电性位于与反铁磁或铁磁有序相关的量子临界点附近，还是其他一些东西，如四极自由度。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.