Regensburg 2025 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 9: Poster

MM 9.69: Poster

Monday, March 17, 2025, 18:30–20:30, P1

Effect of 4f occupancy on L₃ edge of Cerium — •Prathibha Chandrashekhar, Patrik Thunström, Felix Sorgenfrei, and Heike Herper — Department of Physics and Astronomy, Uppsala University, Sweden

The valence 4f electrons in Cerium exhibit a strong itinerant tendency, allowing them to exist in a mixed-valence regime, between localized and delocalized states. This regime hosts correlated electron phenomena which has profound implications on the material’s magnetic, transport, and electronic properties. The shift in 5d orbitals to higher energy levels, due to reduced screening from delocalized 4f electrons, provides critical insights into electronic properties. We study this shift by probing 2p to 5d transition using X-ray Absorption Spectra(XAS). However, accurately modeling the light-matter interaction in such systems remains challenging due to the itinerant nature of the 4f electrons, strong core-hole effects, multiplet interactions, and hybridization dynamics. In this work, we employ advanced theoretical approach that combines density functional theory (DFT) with multiplet ligand-field theory (MLFT). This method enables computation of L₂,₃-edges by constructing and solving single-impurity Anderson model (SIAM) derived from first-principles calculations. Additionally, we investigate sensitivity of the computed spectra to Slater integrals, hybridization effects, and core-hole relaxation, offering new insights into the intricate electronic behavior of Cerium-based systems. PC acknowledges partial funding from Horizon Europe MSCA Doctoral Network grant n.101073486, EUSpecLab, funded by European Union.

Keywords: Simple Anderson Impurity Model; Multiplet Ligand Field Theroy; XAS; Rare earth materials