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O: Fachverband Oberflächenphysik

O 2: Electronic structure of surfaces: Spectroscopy, surface states I

O 2.4: Vortrag

Montag, 9. März 2026, 11:30–11:45, HSZ/0201

From low- to high-energy photoelectron diffraction: Novel theoretical approaches and Kikuchi diffraction analysis — •Trung-Phuc Vo¹, Olena Tkach², Didier Sébilleau³, Olena Fedchenko², Hans-Joachim Elmers², Gerd Schönhense², and Ján Minár¹ — ¹Univ. of West Bohemia in Pilsen, Czech Republic — ²Univ. of Mainz, Germany — ³Univ. of Rennes, France

Time-of-flight momentum microscopy (ToF-MM) enables simultaneous energy- and momentum-resolved mapping of the full photoelectron distribution. Its sensitivity to the strong energy dependence of Kikuchi patterns [1,2] requires advanced theoretical modeling, especially across the broad energy range accessible with modern large-k-field setups [3]. We present a fully relativistic multiple-scattering study of fine diffraction features in core-level photoemission from Ge(100) and Si(100) over kinetic energies from 106 to 4174 eV [4]. Our one-step calculations avoid cluster-size convergence issues and include inelastic scattering to describe pattern broadening. For the first time, we reproduce circular dichroism in the angular distribution of Si(100) 1s with asymmetries up to 31%, and capture both bulk- and surface-sensitive diffraction features. The simulations show good agreement with experimental data obtained using circularly polarized light, demonstrating the robustness of our approach for high-energy photoemission and PED analysis.

[1] O. Tkach et al., Ultramicroscopy 250, 113750 (2023); [2] T.-P. Vo et al., AIP Conf. Proc. 3251, 020005 (2024); [3] T.-P. Vo et al., arXiv:2504.14758 (2025); [4] T.-P. Vo et al., npj Comput. Mater. 11, 159 (2025).

Keywords: PED; CDAD; Kikuchi; Diffraction; Scattering