Dichroism and photoelectron spin-polarization of complex quantum materials

该项目是基于一项联合实验和理论研究，目的是解开光电发射信号与大量实验参数的复杂依赖关系，这些参数可以在现代同步辐射设施中得到特别好的控制和系统的变化，例如实验几何形状，光的偏振，光子能量和获得光电子的自旋偏振。这个多维参数空间的探索需要精心设计的理论方法，必须适应详细的实验。特别是，我们计划研究圆二色性和线性二色性作为轨道角动量的探针，补充自旋极化测量，将观测值与内在拓扑性质联系起来，将这些研究扩展到磁有序系统，并将这些研究与新引入的内在二色性观测值结合起来（TRDAD，iLDAD），其可以提供对电子初始状态属性的甚至更直接的访问。因此，我们将进行系统的国家的最先进的自旋分辨和二色性ARPES实验，以及具体的理论光电发射计算几个原型材料系统具有复杂的物理性质。

This project is based on a joint experimental and theoretical study with the aim to disentangle the complex dependence of the photoemission signal from the noumerous experimental parameters, which can be particularly well controlled and systematically varied at modern synchrotron radiation facilities, e.g. experimental geometry, polarization of the light, photon energy and access to spin-polarization of the photoelectrons. The exploration of this multi-dimensional parameter space requires elaborated theoretical approaches which have to be adapted in detail to the experiment. In particular, we are planning to investigate circular and linear dichroism as probes of orbital angular momentum, complementary to spin polarized measurements, to relate the observables to the intrinsic topological properties, to extend these studies towards magnetically ordered systems, and to combine these studies with newly introduced intrinsic dichroic observables (TRDAD, iLDAD) that may provide an even more direct access to the electronic initial-state properties. Therefore, we will perform systematic state-of-the-art spin-resolved and dichroism ARPES experiments as well as specific theoretical photoemission calculations on several prototypical material systems with complex physical properties.