CAREER: Emergent Quantum Spin-Liquid in Yb-Pyrochlores and Yb-Spinels

职业：镱烧绿石和镱尖晶石中的涌现量子自旋液体

• 批准号: 1350002
• 负责人: Haidong Zhou
• 金额: $ 70万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1350002&HistoricalAwards=false
• 关键词: CAREER; Emergent; Quantum; Spin; Liquid

Technical AbstractAmongst the celebrated exotic phases of condensed matter, of particular recent interest are the quantum spin liquids (QSLs). It is widely believed that extreme quantum entanglement and geometrical frustration lead to QSLs' defining properties: strong spin correlations, the absence of static magnetic moments, and unbroken crystalline symmetry. Despite the intensive studies on QSLs, the response of the QSL state to various perturbations, such as chemical pressure, site disorder, and extra magnetic interactions, has not been thoroughly studied. Moreover, one main obstacle for QSL studies is the shortage of the examples. This award supports an experimental approach for studying the correlations between the local structural variations of the Yb3+ ions and both the perturbation effects on the QSL state in different Yb-pyrochlores and the exotic magnetism of various Yb-spinels. In both cases the geometrically frustrated corner-shared tetrahedral Yb3+-network strongly influences their magnetic properties. The investigator will synthesize, and grow crystals of new Yb-pyrochlores and new Yb-spinels and study two important physical aspects: (i) the nature of their magnetic ground states by using AC susceptibility measurements and neutron scattering; (ii) the local structural variations of the Yb3+ magnetic ions by using the pair distribution function technique. The program will train two graduate students; and aims to attract undergraduate and high school students, particularly minority students, to motivate and expose to the real world of science and technology. This will be acheived in collaboration with the Educational Advanced Program (EAP) and the Tennessee Louis Stokes Alliance for Minority Participation (TLSAMP) program at the University of Tennessee. The investigator will also provide crystals and offer services for training students on crystal growth and crystal processing to a broader scientific community.Non-Technical AbstractThe understandings of the physical properties of quantum matters have been at the forefront of modern condensed matter physics research. One recent example is quantum spin liquids (QSLs): a unique state with strong spin correlations but without static magnetic order. The geometrical arrangements of the magnetic atoms prevent them to direct their magnetic moment, the materials are magnetically frustrated. The exotic properties of QSLs appear only at extremely low temperatures, and are expected to be sensitive to various perturbations. Moreover, one main obstacle for QSL studies is the shortage of examples. This program will explore new QSL materials and study the perturbation effects on them. Single crystals of the QSL candidates will be grown in the investigator's laboratory and then will be studied by various methods under low temperatures and high magnetic fields. The program will train two graduate students; and aims to attract undergraduate and high school students, particularly minority students, to motivate and expose them to the real world of science and technology. This will be acheived in collaboration with the Educational Advanced Program (EAP) and the Tennessee Louis Stokes Alliance for Minority Participation (TLSAMP) program at the University of Tennessee. The investigator will also provide crystals and offer services for training students on crystal growth and crystal processing to a broader scientific community.

技术摘要的技术敏感物质的著名外来阶段特别感兴趣的是量子自旋液体（QSL）。人们普遍认为，极端的量子纠缠和几何挫败感导致QSL的定义特性：强旋相关性，没有静态磁矩的缺失以及不间断的晶体对称性。尽管对QSL进行了深入的研究，但尚未对QSL状态对各种扰动的反应，例如化学压力，现场障碍和额外的磁相互作用，尚未得到彻底研究。此外，QSL研究的一个主要障碍是示例短缺。该奖项支持一种实验方法，用于研究YB3+离子的局部结构变化与对不同YB-Pyrochlores中QSL状态的扰动效应与各种YB-Spinel的外来磁性之间的相关性。在这两种情况下，几何沮丧的角共享的四面体YB3+ - 网络都会强烈影响其磁性。研究者将合成新的YB-Pyrochlores和New YB-Spinels的晶体，并研究两个重要的物理方面：（i）通过使用AC敏感性测量和中子散射，其磁接地状态的性质； （ii）使用配对分布函数技术的YB3+磁离子的局部结构变化。该计划将培训两名研究生；旨在吸引本科生和高中生，尤其是少数族裔学生，以激励和暴露于科学技术的现实世界。这将与田纳西大学的教育高级计划（EAP）和田纳西州路易斯·斯托克斯联盟（TLSAMP）计划合作实现。研究人员还将为培训学生提供晶体生长和水晶处理的服务，为更广泛的科学界提供有关晶体生长和晶体加工的服务。非技术摘要对量子问题物理特性的理解一直处于现代冷凝物质物理学研究的最前沿。最近的一个例子是量子自旋液体（QSL）：具有强旋相关性但没有静态磁性的独特状态。磁原子的几何排列阻止它们引导其磁矩，材料在磁性上被挫败。 QSL的外在特性仅在极低的温度下才出现，并且有望对各种扰动敏感。此外，QSL研究的主要障碍是示例短缺。该计划将探索新的QSL材料，并研究对它们的扰动影响。 QSL候选物的单晶将在研究人员的实验室中生长，然后在低温和高磁场下通过各种方法研究。该计划将培训两名研究生；旨在吸引本科生和高中生，尤其是少数族裔学生，以激励和暴露于科学技术的现实世界中。这将与田纳西大学的教育高级计划（EAP）和田纳西州路易斯·斯托克斯联盟（TLSAMP）计划合作实现。研究人员还将为培训学生提供水晶增长和水晶加工的水晶和服务，为更广泛的科学界提供有关水晶的增长和水晶处理。