Investigation of the electronic properties of iron-based superconductors with focus on the interaction of superconducting and magnetic order parameters in the coexistence phase

室温超导性是当前科学的主要目标之一。这些超导体可以无电阻地传导电流。为了实现这一目标，全面了解（非常规）超导性是必要的。40年前人们就知道超导性和磁性是密切相关的。在这个项目中，这两种现象的相互作用将进行理论和实验研究。使用局部探针方法的实验将在铁基超导体上进行，以确定纳米尺度上的电子特性。特别是，将进行μ子自旋弛豫和穆斯堡尔谱实验。铁基超导体将这两种现象的接近程度发挥到了极致，因为相同的电子是超导的，并且是磁有序的。通过施加高压，可以探测两种电子状态的相互作用。理论上描述了这些相互作用。这将通过使用波函数方法以及微观计算来完成。理论和实验的结合将有助于加深对铁基超导体超导电性的起源和性质的认识。这些知识可以用来描述其他非常规的超导体，从而使人们对超导性有一个普遍的了解，这将有望在未来产生一种室温超导体。

Room temperature superconductivity is one major objective of current science. These superconductor would conduct the electrical current without any resistance. To reach this goal, a comprehensive understanding of (unconventional) superconductivity is necessary. It is known for 40 years now that superconductivity and magnetism are closely related. In this project the interaction of both phenomena will be theoretically and experimentally investigated. Experiments using local probe methods will be conducted on iron-based superconductors to determine the electronic properties on a nanoscopic length scale. In particular, muon spin relaxation and Moessbauer spectroscopy experiments will be conducted. The iron-based superconductors taking the closeness of both phenomena to its extremes as the same electrons are superconducting and magnetically ordered. By applying high pressures the interaction of both electronic states can be probed. These interaction is theoretically described. This will be done by using wave function methods as well as by microscopic calculations. The combination of theoretical and experimental investigations will enhance the knowledge about the origin and properties of the superconductivity in the iron-based superconductors. These knowledge can be used to describe other unconventionell superconductors to take a step forward to a general understanding of superconductivity which will hopefully result in a romm temperature superconductor in the future.