SKM 2023 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 2: Focus: Dislocations in Ceramics: Mechanics, Structures and Functionality (joint session KFM/MA)

KFM 2.1: Hauptvortrag

Montag, 27. März 2023, 14:30–15:00, POT 51

Formation of conducting channels along of dislocations in SrTiO₃ — •Christian Rodenbücher¹, Kristof Szot², Gustav Bihlmayer³, and Carsten Korte¹ — ¹Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-14) — ²University of Silesia, Institute of Physics, 41-500 Chorzów, Poland — ³Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-1), 52425 Jülich, Germany

SrTiO₃ has become one of the most extensively studied metal oxides due to its exceptional electronic properties, which hold promising potential for applications in energy conversion and electronics. A key feature of SrTiO₃ is that its electronic transport properties are closely related to oxygen nonstoichiometry, which can be manipulated via redox reactions. Our nanoscale investigations on crystals and ceramics employing imaging techniques such as local-conductivity atomic force microscopy (LC-AFM) reveal that the reduction process is highly complex and heterogeneous on the nanoscale. Along extended defects such as dislocations there are easy reduction sites where oxygen vacancies are preferentially generated. In this way, filaments with high conductivity evolve around the dislocations in the originally insulating matrix and act as nanoscale short circuits. Upon application of mechanical stress, these filaments can even be moved through the crystal together with the dislocations. These findings not only can explain failure mechanisms in solid oxide electrolytes, but also raise fundamental questions regarding the mechanisms of electronic transport and superconductivity in self-doped transition metal oxides.