量子自旋液体是指在量子涨落和自旋阻挫共同作用下的反铁磁系统，在零温下呈现的一种奇异的强量子纠缠的自旋无序基态。它是当代凝聚态物理重要前沿课题之一，寻找理想的量子自旋液体材料是该领域的一个重大挑战。申请人最近发现了一个基于强自旋轨道耦合的新型量子自旋液体巨大家族——稀土氧硫族化合物体系，这是目前已知的量子自旋液体候选材料中化学式最简单和结构最理想的体系。本项目计划全面系统地开展该家族材料的合成和晶体生长，进行强磁场下的磁共振和热力学测量，确定体系的各向异性自旋交换耦合参数，研究这种新型量子自旋液体的基态性质和激发态低能自旋动力学，并尝试开展金属化研究。本研究预计将揭示量子自旋液体的一些奇异行为，有助于理解量子自旋液体与高温超导机制的内在关联，同时也为发展面向新型量子信息和量子计算的重大潜在应用打下基础。

Quantum spin liquid (QSL) is an exotic spin-disordered ground state with strong quantum entanglement. It stems from strong quantum fluctuations and spin frustrations in an antiferromagnetic system. The study of QSL has always been one of the key frontiers in modern condensed matter physics. And the search for ideal QSL materials is a major challenge in this field in the last few decades. Very recently we revealed a large family of QSL candidates with strong spin-orbit coupling, i.e., rare-earth chalcogenides. The family has the simplest chemical formula and the most ideal structure among the known QSL candidates so far. In this project, we plan to make a systematic sample synthesis and crystal growth. And we will carry out magnetic resonance measurements under high magnetic fields, including nuclear magnetic resonance and electron spin resonance, and thermodynamics measurements under high magnetic fields. The study will determine anisotropic spin exchange coupling parameters, and reveal the novel properties of QSL ground state and low-energy spin dynamics in the excited states. Meanwhile, we will also initialize the metallization of the new-type QSL materials. It is expected that the study will uncover some exotic effects of QSL and is much helpful to the understanding of the ultimate correlation between QSL and high temperature superconductivity. And we also expect that the study can set a foundation for the potential QSL applications towards quantum information and quantum computing in the future.