Regensburg 2025 – scientific programme
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DS: Fachverband Dünne Schichten
DS 11: Thermoelectric and Phase Change Materials
DS 11.1: Talk
Thursday, March 20, 2025, 15:00–15:15, H3
Bond strength and force constants in RESbS — •Franziska Zahn1, Christopher Benndorf2, Hans H. Falk1, Konrad Ritter1, Sergiu Levcenko1, Edmund Welter3, Oliver Oeckler2, and Claudia S. Schnohr1 — 1Felix Bloch Institute for Solid State Physics, Leipzig University, Germany — 2Institute of Inorganic Chemistry and Crystallography, Leipzig University, Germany — 3Deutsches Elektron Synchrotron DESY, Hamburg, Germany
Our recent study on bond strength in different materials has shown that elemental Sb exhibits characterics of regular covalent and multicenter bonding based on the behavior of force constants with increasing interatomic distance. RESbS are Sb-containing rare-earth (RE) pnictide chalcigenides that show special electronic and magnetic properties. They consist of different layeres, including Sb monolayers that alternate with RE-S double layers. To study the structural and vibrational properties of RESbS with RE = La, Ce, Pr, and Nd in more detail, extended X-ray absorption fine structure spectroscopy (EXAFS) was performed at the Sb K-edge at ten different temperatures ranging from 20 to 295 K. The temperature dependence of the bond length variation σ2 (mean square relative displacement) was evaluated using a correlated Einstein model, providing static disorder and force constants. The behavior of the force constants with incrasing interatomic distance is compared to other materials and to elemental Sb in particular. This contributes to the fundamental understanding of physical properties of RESbS and their potential origin.
Keywords: RESbS; bonding; force constants; atomic vibrations; X-ray absorption spectroscopy