Crystal structure, phase diagram, electronic, magnetic and superconducting properties of AFe2-xMxAs2 -a joint experimental and theoretical study

该项目将最近发现的铁磷属元素化物超导体的实验研究和理论研究结合起来，结合固态化学和固态物理的方法。建议的研究重点是AFe 2-x MxAs 2（A= Ca，Sr，Ba，Eu; M= Mn，Co，Ni，Ru，Rh，Ir）系列化合物，并将研究晶体结构，化学取代，掺杂，内部和外部压力与相应的电子，磁性和超导性能之间的关系。高质量的单晶样品将被合成，并通过各种技术仔细表征。除了自己的热力学和输运测量，这些单晶将被SPP的其他参与者用于多种光谱测量（光学，NMR，μSR，Mößbauer，dHvA）。从头计算电子结构计算将伴随着实验研究的所有阶段，以获得基于微观的物理性质的理解，并指导新化合物的修改。基于现实的结构模型，能带结构的结果将提供准确的输入（相关的轨道和耦合，DOS，费米面），为进一步建模的不同水平的近似。从带结构的结果与实验数据的比较，我们期待在这些新的高温超导体的结构性能关系的基本见解。

This project connects experimental investigations and theoretical studies of the recently discovered iron pnictide superconductors joining approaches from solid state chemistry and solid state physics. The suggested study focuses on the AFe2-x MxAs2 (A= Ca, Sr, Ba, Eu; M= Mn, Co, Ni, Ru, Rh, Ir) family of compounds and will investigate the relation between crystal structure, chemical substitution, doping, internal as well as external pressure and the respective electronic, magnetic and superconducting properties. High quality single crystalline samples will be synthesized and carefully characterized by various techniques. In addition to own thermodynamic and transport measurements, these single crystals will be used by other participants of the SPP for a multitude of spectroscopic measurements (optics, NMR, μSR, Mößbauer, dHvA). Ab initio electronic structure calculations will accompany the experimental studies in all stages to obtain a microscopically based understanding of the physical properties and guide the modification of new compounds. Based on realistic structural models, the band structure results will provide accurate input (relevant orbitals and couplings, DOS, Fermi surfaces) for further modelling on different levels of approximation. From the comparison of the band structure results with the experimental data we expect fundamental insights in the structure property relations of these new high temperature superconductors.