VUV light source for high-resolution (energy/momentum/spatial) photoemission

申请人小组的研究重点是半导体衬底上超薄外延吸附层的合成和实验，从亚单层覆盖层到厚度为10 nm的薄膜。科学兴趣的目标是一维原子链、具有强电子关联的二维三角晶格以及具有自旋极化边缘和边界态的拓扑绝缘体的不寻常的电子性质。这些研究的主要实验方法是角分辨光电子能谱(ARPES)和扫描隧道显微镜/光谱学(STM/STS)。由于其固有的表面特性，所有的薄膜系统都必须在原位(即在超高真空条件下)合成和研究。目前用于这些实验的ARPES系统在空间和能量分辨率以及有效样品吞吐量方面正在达到其极限。因此，计划通过一个专门用于真空紫外线(VUV)辐射的最先进的光源来升级该系统，从而克服目前的限制，促进极大地改善研究机会。

The research focus of the applicant's group is on synthesis of and experiments on ultrathin epitaxial adsorbate layers on semiconductor substrates, from sub-monolayer coverages to film thicknesses of several 10 nm. The scientific interest is targeted at unusual electronic properties of 1D atomic chains, 2D triangular lattices with strong electronic correlations, and topological insulators with their spin-polarized edge and boundary states. The central experimental methods for these investigations are angle-resolved photoelectron spectroscopy (ARPES) and scanning tunneling microscopy and spectroscopy (STM/STS). Due to their intrinsic surface character all film systems have to be synthesized and studied in situ (i.e., under ultra high vacuum conditions). The current ARPES system used for these experiments is reaching its limits in terms of spatial and energy resolution as well as with respect to efficient sample throughput. Therefore, it is planned to upgrade the system by a dedicated state-of-the art light source for vacuum ultraviolet (VUV) radiation, allowing to overcome the present limitations and facilitating greatly improved research opportunities.