非常规超导体的材料学和物理性质研究一直是凝聚态物理的前沿领域，其中铁基超导体是当前研究的热点。本项目使用高压和核磁共振相结合的方法，以铁基超导材料，特别是1111结构铁基超导体为研究对象，对其超导配对的性质和机制进行研究。具体开展的工作如下：(1)制备系列LaFeAsO1-xFx高质量样品，测量其在化学掺杂和物理压力作用下的结构相变，反铁磁相变和超导，构建精确的掺杂-压力-温度三维相图；(2)利用高压下的核磁共振技术，判断1111结构中反铁磁与超导的关系是竞争还是共存，研究自旋涨落、轨道涨落与超导的关系，获得可能的超导电子配对机制；（3）通过测量奈特位移与自旋晶格弛豫率，得到超导能隙和自旋配对对称性的信息。对于铁基超导体这样一个多带体系，我们系统性的高压核磁共振研究将有助于全面了解铁基材料的物理性质，澄清一些悬而未决的问题，为超导机理的阐明提供线索。

Materials and physical properties of unconventional superconductors have received great attentions in the field of condensed matter physics, and the iron-based superconductors is currently the front area. This project makes a combination of the high pressure technique and the Nuclear Magnetic Resonance method to study the iron-based superconductors, especially the 1111 structure materials.The research will be focused on the intrinsic properties of cooper pair and the mechanism of electron pairing. Our work will be as follows: (1) Prepare LaFeAsO1-xFx high quality samples, while study the properties of structural phase transition, antiferromagnetic phase transition and superconductivity under chemical pressure and physical pressure. A precise 3D doping-pressure-temperature phase diagram will be built; (2) Use high pressure NMR techniques to explore the relationship between AFM and superconductivity is whether competition or coexistence, and research the role of spin fluctuation and orbital fluctuation on superconductivity; (3) by measuring the Knight shift and spin-lattice relaxation rate we will abtain the information about superconducting pairing symmetry. Iron-based superconductors is a multi-band system, the systematic high-pressure NMR studies will contribute to a comprehensive understanding of the properties of iron-based materials, clarify some outstanding issues, and provide clues for the superconducting mechanism.