Regensburg 2025 – scientific programme

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MA: Fachverband Magnetismus

MA 4: Electron Theory of Magnetism and Correlations

MA 4.2: Talk

Monday, March 17, 2025, 09:45–10:00, H19

Investigation of crystalline environment for Fe oxides using XAS and XPS:A DFT+MLFT approach — •Hamza Zerdoumi, Ruiwen Xie, and Hongbin Zhang — Institute of Materials Science, TU Darmstadt,Germany

Fe oxides are versatile materials with applications spanning catalysis, memory storage, and photoelectrochemical decomposition of seawater for clean hydrogen production. Taking Fe₂O₃ as an example, there exist five distinct phases, i.e., α-Fe₂O₃, β-Fe₂O₃, γ-Fe₂O₃, є-Fe₂O₃, and ζ-Fe₂O₃, each exhibiting unique properties. Therefore, it is intriguing to clarify how the local crystalline environment can shape the electronic structure and hence tailor the corresponding functionalities. In this study, we simulate X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) spectra using a combination of density functional theory (DFT) and multiplet ligand field theory (MLFT). By analyzing individual spectral bands corresponding to iron sites in various crystal structures, we examine the correlation between local symmetry and the simulated spectra. Our work highlights how variations in local environments influence the spectroscopic features of iron oxide polymorphs, offering valuable insights into their diverse properties.

Keywords: X-ray Photo-electron Spectroscopy; X-ray Absorption Spectroscopy; DFT TO MLFT; Local Crystalline Environment; Iron oxide