Novel Thermal Transport Phenomena in Quantum Materials

摘要：电子不仅携带电能，而且携带能量。电子的这种特性是对量子材料的有力探测。用热移动电子会产生电压或显示固体中的热传导。这些移动的电子可能在磁场作用下改变运动方向，导致横向电压和热传导。这些新的热输运性质对于探测强相关量子材料的基态至关重要。该研究为研究强相关效应和拓扑之间的相互作用打开了大门，为未来的电子产品寻找新的量子相、新的拓扑相和新的多功能。该项目还提供了在这个量子世界的科学和技术方面培养本科生和研究生的机会。通过让本科生参与研究，创造机会促进女性和少数民族在科学和工程领域的融合，将当地学校的学生带到实验室，并将研究成果传达给更广泛的公众，该团队为公众带来了强相关材料的进步，并培养了对量子科学和凝聚态物理领域的兴奋、意识和兴趣。技术摘要：本研究项目旨在利用新型热输运特性研究强相关材料。结合强相关材料和拓扑量子材料的研究领域，研究小组将利用热电效应和热霍尔效应来揭示最近观察到的强相关材料新现象的物理起源：(1)近藤绝缘体中的量子振荡；(2)未掺杂和掺杂的莫特绝缘子存在较大的热霍尔效应；(3)量子自旋液体中的外来热输运；(4) Kagome金属的平-淡现象。这些方向是凝聚态物理中长期存在的难题的令人兴奋的新发展。他们对电荷中性准粒子在强相互作用态中的作用有着同样的争论：是什么带来了这些有趣的现象：马努子、声子、波格留博夫准粒子，甚至是马约拉纳激发。研究任务将回答以下问题：(1)近藤绝缘体中磁场驱动的绝缘体-金属过渡的性质是什么？(2)莫特绝缘未掺杂铜中热流强霍尔信号的原因是什么？(3) Kagome量子自旋的基本激发是费米子激发还是玻色子激发？(4) Kagome金属中平带的实验特征是什么？这些问题的答案最终将提供强相关材料的电子和磁性基态的大图景。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 Abstract: Electrons carry not only electricity but also energy. This property of electrons is a powerful probe for quantum materials. Moving the electrons with heat generates electrical voltages or reveals thermal conductions in the solids. These mobile electrons may change the moving directions under a magnetic field, leading to transverse electrical voltages and thermal conductions. These novel thermal transport properties are essential to detect and probe the ground state of strongly correlated quantum materials. The research brings the potential to open the door to studying the interplay between strong-correlation effects and topology in the search for new quantum phases, novel topological phases, and new multi-functionalities for future electronics. The project also provides opportunities to train undergraduate and graduate students in the science and technology of this quantum world. By involving undergraduates in research, creating opportunities to promote the integration of women and minorities in careers in science and engineering, bringing local school students to laboratories, and communicating research to the broader public, the team brings the general public the advancements in strongly correlated materials and develops excitement, awareness, and interest in the field of quantum science and condensed matter physics. Technical Abstract: The research project aims to investigate strongly correlated materials using novel thermal transport properties. Bridging the research fields of strongly correlated materials and topological quantum materials, the research team will use the thermoelectric effect and thermal Hall effect to reveal the physical origin of recently observed novel phenomena of strongly correlated materials: (1) quantum oscillations in Kondo insulators; (2) large thermal Hall effects in undoped and doped Mott insulators; (3) exotic thermal transport in quantum spin liquid; and (4) flat-bland phenomena of Kagome metals. These directions are exciting new developments in long-standing puzzles in condensed matter physics. They share the same debate about the role of the charge-neutral quasiparticles in the strongly interacted states: what carries these interesting phenomena: magnon, phonon, Bogoliubov quasiparticles, or even Majorana excitations. The research tasks will answer these questions: (1) What is the nature of the magnetic-field-driven insulator-metal-transition in Kondo insulators? (2) What causes strong Hall signals of the heat current in Mott insulating undoped cuprates? (3) Are the fundamental excitations fermionic or bosonic in Kagome quantum spin liquid? (4) What are the experimental signatures of the flat band in Kagome metals? Answers to these questions will eventually provide the big picture of the electronic and magnetic ground states of strongly correlated materials.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.