SKM 2023 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 4: Focus: Domains and Domainwalls in (Multi)Ferroic II

KFM 4.6: Vortrag

Dienstag, 28. März 2023, 11:05–11:25, POT 51

Electronic transport at pristine neutral ferroelectric domain walls in lead titanate — •Sabine Körbel¹ and Christophe Adessi² — ¹Institute of Condensed Matter Theory and Optics, Friedrich Schiller University Jena, Germany — ²Institut Lumière Matière, Université Claude Bernard Lyon I, France

Ferroelectric domain walls are intrinsic interfaces that form spontaneously in ferroelectric materials, such as, for example, perovskite oxides. Whereas the ferroelectric perovskite oxide itself is an insulator, ferroelectric domain walls can be electrically conductive, as numerous experiments on different perovskite oxides have shown. This domain-wall conduction could serve, e.g., for charge-carrier transport in future photovoltaic absorbers. We investigated, using ab initio calculations based on Green’s functions, the electronic transport along and through neutral ferroelectric domain walls in the prototype ferroelectric perovskite oxide PbTiO₃, and determined how the domain walls change the electronic transmission of bulk PbTiO₃ and the I-V curves of an ultrathin metal/perovskite/metal sandwich structure. We find that pristine neutral domain walls have a moderate effect on electronic transmission and I-V curve (within about one order of magnitude), much smaller than the experimentally measured conductivity increase at the walls by several orders of magnitude. We suggest that the measured conductivity increase does not directly originate in the electronic structure of the pristine neutral domain walls, but is caused by secondary effects, such as the accumulation of free charge carriers and/or the segregation of charged defects at the walls.