Regensburg 2025 – scientific programme

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DS: Fachverband Dünne Schichten

DS 13: Poster

DS 13.58: Poster

Thursday, March 20, 2025, 18:00–20:00, P1

Bond Confinement Induced Tayloring of Optical Properties — •Thomas Schmidt, Peter Kerres, Felix Hoff, Julian Mertens, Yiming Zhou, Maria Häser, and Matthias Wuttig — I. Institute of Physics (IA), RWTH Aachen University, Germany

Chalcogenide materials, such as GeTe and Sb₂Te₃, exhibit a broad range of properties that enable applications in thermoelectrics and phase change material (PCM) memory storage, where rapid and reversible switching between amorphous and crystalline states alters optical and electrical characteristics. Recent studies on textured chalcogenide thin films have focused on understanding structure-property relationships, particularly how properties evolve with film thickness. It is also explored how confinement influences atomic arrangement and bonding. Changes in bonding, particularly the transition from metavalent to covalent-like bonding, are linked to significant variations in material properties with decreasing thickness. In this work, we investigate the optical contrast of chalcogenide films by analyzing the thickness-dependent changes in the dielectric function. These findings are compared with the dielectric function of a mono-elemental system molecular beam epitaxy (MBE)-grown Bi films with thicknesses ranging from 2 to 30 nm to establish a link between bonding and optical properties.

Keywords: Metavalent Bonding; Dielectric Function; Tellurides; Confinement; Material Design