Magnetic excitations on 2H-NbSe2 - from adatoms and molecules to magnetically coupled nanostructures on a type II superconductor

过渡金属二卤化物2H-NbSe_2是一种研究较多的具有各向异性S波超导电性的二维II型超导体。在这个项目中，我们将通过提供高能量和空间分辨率的扫描隧道显微镜和光谱(STM/STS)来探索顺磁吸附原子、分子和人造纳米结构与这种特殊类型的超导体的局部相互作用。我们将通过解析磁性基态和激发态来识别与衬底的不同耦合模式以及诱导多体状态的空间扩展。借助于垂直磁场，我们将使衬底进入涡旋状态。这使得我们可以在逐渐变化的环境中研究类似的磁性杂质，从具有高B场的涡旋核，到磁场减弱而超导电性增强的区域，以及仍然存在B场的超导区域。最后，我们将研究杂质之间的短程和长程耦合机制，这强烈依赖于2H-NbSe2超导电性的各向异性，并使具有设计的自旋性质和拓扑相的纳米结构的构建成为可能。

The transition metal dichalcogenide 2H-NbSe2 is a well-studied type II superconductor with anisotropic s-wave superconductivity, which is two-dimensional-like. Within this project, we will explore the local interaction of paramagnetic adatoms, molecules and artificial nanostructures with this particular type of superconductor by means of scanning tunneling microscopy and spectroscopy (STM/STS), which offers high energetic and spatial resolution. We will resolve magnetic ground and excited states to identify different coupling regimes with the substrate and the spatial extend of induced many-body states. By means of a perpendicular magnetic field, we will bring the substrate into the vortex state. This allows us to study similar magnetic impurities in gradually changing environments, from the vortex core with high B-fields, to regions of decreasing fields and increasing superconductivity, and superconducting regions with still persisting B-fields. Finally, we will investigate short- and long-range coupling mechanisms between impurities, which strongly rely on the anisotropic character of the superconductivity in 2H-NbSe2, and enable the construction of nanostructures with designed spin properties and topological phases.