Microscopic investigation of quantum materials based on nuclear magnetic resonance

我们基础研究的科学目标是理解由量子力学驱动的固体的非直觉行为。我们智力追求的两大支柱是量子磁学和奇异超导。前者研究的是受挫的“自旋液体”中的磁矩，这些液体在绝对零度附近继续波动而不经历相变。本质上，这些磁铁的行为就好像它们不是磁铁一样。破译它们的神秘性质是当今量子材料研究的圣杯。后者寻求理解在某些种类的氧化铜和铁镍中电阻突然消失背后的机制。******NSERC发现基金使我们能够基于一种叫做核磁共振（NMR）光谱的微观探针来研究这些基本的物理问题。核磁共振是在医院使用的磁共振成像（MRI）背后的基本原理。核磁共振在微观层面深入了解电子和原子的行为方式方面是非常出色的。我们使用核磁共振在极端环境下进行研究量子材料，如接近绝对零度的低温、超高压和/或高磁场。******我的学生在我们装备精良的低温核磁共振实验室进行内部研究。他们可以无限制地使用三套核磁共振光谱仪，三种可以产生高达16特斯拉的高磁场的超导磁体，3到9 GPa的高压电池，以及顶部装载的氦-3和稀释冰箱，基础温度分别低至0.35 K和0.009 K。这些基础设施的总价值超过200万美元。他们的运营成本非常高，但对我的学生和加拿大的回报也是如此。我们卓越的研究能力使我的学生能够与世界领先的研究人员建立高水平的合作，并发表高水平的论文。广泛的设备阵列也帮助我的学生通过动手培训解决问题的能力，在电子，设计，制造，安装和维护低温齿轮，和复杂的电子计算机接口。从本科生到博士后研究人员，我对各个层次的学生进行了全方位的培训，这为他们提供了各种各样的职业机会。******在未来的5年里，我建议扩大我们的研究业务，无论是在小组的规模和范围。在保持kagome自旋液体研究实力的同时，我们正在冒险进入一个新的令人兴奋的方向，即研究焦绿石晶格中的受挫磁性。鉴于研究领域的最新进展，我们还计划将注意力重新集中在铜基和铁基高温超导体的研究上。

The scientific goal of our fundamental research is to understand the non-intuitive behavior of solids driven by quantum mechanics. Two major pillars of our intellectual pursuit are quantum magnetism and exotic superconductivity. The former examines magnetic moments in frustrated “spin liquids” that continue fluctuating near absolute zero without undergoing a phase transition. In essence, these magnets behave as if they were not a magnet. Deciphering their mysterious properties is the holy grail of today's quantum materials research. The latter seeks understanding of the mechanisms behind sudden disappearance of electrical resistance in some classes of copper-oxides and iron-pnictides. ******NSERC Discovery Grant enables us to investigate these fundamental problems of physics based on a microscopic probe called Nuclear Magnetic Resonance (NMR) spectroscopy. NMR is the underlying principle behind the magnetic resonance imaging (MRI) used in hospitals. NMR is exceptional at gaining deep insight at microscopic levels into why electrons and atoms behave the way they do. We investigate quantum materials using NMR conducted in extreme environments, such as low temperatures near absolute zero, ultra high pressure, and/or high magnetic field. ******My students conduct in-house research in our phenomenally well-equipped cryogenic NMR laboratory. They have unlimited access to three sets of NMR spectrometers, three types of superconducting magnets which can generate high magnetic fields up to 16 Tesla, high pressure cells to reach 3 to 9 GPa, and top-loading helium-3 and dilution refrigerators with the base temperature as low as 0.35 K and 0.009 K, respectively. The total value of these infrastructure exceeds $2-million. Their operational cost is very high, but so are the rewards to my students and Canada. Our superb research capabilities allow my students to establish high caliber collaborations with the world's leading researchers and publish high profile papers. The broad array of equipment also helps my students develop problem solving skills through hands-on training on the electronics, designing, manufacturing, installation and maintenance of cryogenic gears, and computer interfacing of sophisticated electronics. The versatile nature of my student training at all levels from undergraduate to postdoctoral researchers leads to a wide variety of career opportunities for them. ******In the coming 5 years, I propose to extend our research operation both in terms of the group size and scope. We are venturing into a new exciting direction of research on frustrated magnetism in the pyrochlore lattice, while maintaining our strength in research on kagome spin liquids. We also plan to refocus our attention on investigations of copper- and iron-based high temperature superconductors in view of the recent developments in the research field.