Dichroism and photoelectron spin-polarization of complex quantum materials

本项目是基于实验和理论的联合研究，旨在解开光电信号与众多实验参数的复杂依赖关系，这些参数在现代同步辐射设施中可以很好地控制和系统地变化，例如实验几何，光的偏振，光子能量和光电子的自旋极化。这个多维参数空间的探索需要详细的理论方法，必须适应实验的细节。特别是，我们计划研究圆形和线性二色性作为轨道角动量的探测，补充自旋极化测量，将观测值与本征拓扑性质联系起来，将这些研究扩展到磁有序系统，并将这些研究与新引入的本征二色性观测值（TRDAD, iLDAD）结合起来，这可能提供更直接的访问电子初始状态性质。因此，我们将对几种具有复杂物理性质的原型材料系统进行系统的自旋分辨和二色ARPES实验以及具体的理论光发射计算。

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.