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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 16: Crystal Structure Defects / Real Structure / Microstructure I

KFM 16.4: Talk

Wednesday, March 20, 2024, 16:10–16:30, E 124

Temperature-dependent Peierls Distortion in the Phase Change Material In₃SbTe₂ — •Maria Häser¹, Martin Etter², Henrik Jeppesen², Sebastian Geisler³, Oliver Oeckler³, and Matthias Wuttig¹ — ¹I. Institute of Physics (IA), RWTH Aachen University, Germany — ²Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany — ³Faculty of Chemistry and Mineralogy, Institute of Mineralogy, Crystallography and Materials Science, Leipzig University, Germany

In recent years, interest in chalcogenide-based phase change materials (PCMs) has increased in photonic applications due to their significant difference in optical properties between the amorphous and crystalline phases. A promising candidate for photonic devices is In₃SbTe₂ (IST), which is a plasmonic PCM with metallic properties in the crystalline phase and semiconducting properties in the amorphous state. Using synchrotron radiation, the temperature-dependent atomic arrangement of crystalline IST has been investigated. The simulation of measured Powder X-Ray Diffraction (P-XRD) and Pair Distribution Function (PDF) data allows a direct comparison of the average and the local atomic arrangement: Although IST crystallizes in NaCl structure type (space group Fm-3m (225)) on average, we report local deviations from this structure. These Peierls-like deviations increase with increasing temperature. This finding can explain the temperature dependent behavior of IST and similar materials.

Keywords: Powder XRD (P-XRD); Pair Distribution Function (PDF); Synchrotron Techniques