Zumbülte A, Schmidt A B, Donath M
Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany.
Rev Sci Instrum. 2015 Jan;86(1):013908. doi: 10.1063/1.4906508.
We present a method to determine the electron beam divergence, and thus the momentum resolution, of an inverse-photoemission setup directly from a series of spectra measured on Cu(111). Simulating these spectra with different beam divergences shows a distinct influence of the divergence on the appearance of the Shockley surface state. Upon crossing the Fermi level, its rise in intensity can be directly linked with the beam divergence. A comparison of measurement and simulation enables us to quantify the momentum resolution independent of surface quality, energy resolution, and experimental geometry. With spin resolution, a single spectrum taken around the Fermi momentum of a spin-split surface state, e.g., on Au(111), is sufficient to derive the momentum resolution of an inverse-photoemission setup.
我们提出了一种方法，可直接从在Cu(111)上测量的一系列光谱确定逆光电子发射装置的电子束发散度，进而确定动量分辨率。用不同的束发散度模拟这些光谱，结果表明发散度对肖克利表面态的外观有显著影响。当穿过费米能级时，其强度的增加可直接与束发散度相关联。测量值与模拟值的比较使我们能够在不考虑表面质量、能量分辨率和实验几何结构的情况下量化动量分辨率。对于自旋分辨率，在自旋分裂表面态（例如在Au(111)上）的费米动量附近获取的单个光谱就足以得出逆光电子发射装置的动量分辨率。
