Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
Rev Sci Instrum. 2023 Mar 1;94(3):037101. doi: 10.1063/5.0131463.
The paper under discussion promises a spin- and angle-resolved inverse-photoemission (IPE) setup, where the spin-polarization direction of the electron beam used for excitation "can be tuned to any preferred direction" while "preserving the parallel beam condition." We support the idea to improve IPE setups by introducing a three-dimensional spin-polarization rotator, but we put the presented results to the test by comparing them with the literature results obtained by existing setups. Based on this comparison, we conclude that the presented proof-of-principle experiments miss the target in several aspects. Most importantly, the key experiment of tuning the spin-polarization direction under otherwise allegedly identical experimental conditions causes changes in the IPE spectra that are in conflict with existing experimental results and basic quantum-mechanical considerations. We propose experimental test measurements to identify and overcome the shortcomings.
本文讨论的论文提出了一种自旋和角度分辨逆光电发射 (IPE) 装置，其中用于激发的电子束的自旋极化方向“可以被调谐到任何所需的方向”，同时“保持平行束条件”。我们支持通过引入三维自旋极化旋转器来改进 IPE 装置的想法，但我们通过将呈现的结果与通过现有装置获得的文献结果进行比较来对其进行测试。基于这种比较，我们得出结论，所呈现的原理验证实验在几个方面都没有达到目标。最重要的是，在据称相同的实验条件下调整自旋极化方向的关键实验导致 IPE 光谱发生变化，这与现有实验结果和基本量子力学考虑相矛盾。我们提出了实验测试测量来识别和克服这些缺点。
