SKM 2021 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 1: Focus Session I: Ferroics - Domains and Domain Walls
KFM 1.6: Vortrag
Dienstag, 28. September 2021, 12:00–12:15, H2
Conductivity of ferroelectric domain walls in the lacunar spinel GaV4S8 — •Lukas Puntigam, Donald Evans, Markus Altthaler, Somnath Ghara, Lilian Prodan, Vladimir Tsurkan, Stephan Krohns, and Istvan Kézsmárki — University of Augsburg, 86159, Augsburg, Germany
Ferroelectric domain walls, which can be written, tuned or erased at will, are being considered as functional building blocks for nano devices. Especially, the case of conductive domain walls, where their spatially confined electronic responses, that differ from the bulk of the host material, caused the idea of domain wall for nanoengineering.
To date, the origin for such increased conductivity in ferroelectrics domain walls has been attributed to the formation of screening charges driven by polar discontinuities.
Here, we discuss how other phenomena, such as strain, could induce enhanced conductivity of domain walls, using the lacunar spinel GaV4S8 as a template system. This system exhibits ferroelectric domain pattern below the Jahn-Teller transition at 42 K. Temperature dependent conductive and piezoresponse force microscopy, as well as local I(V)-spectroscopy, are employed to understand the local conductivity. We reveal at low temperatures that the conductivity is non-trivial consistent with the conventional polar-discontinuity approach, but rather - at secondary domain walls - is consistent with a strain-based mechanism. This provides a new mechanism on generating conductivity at domain walls, which is not limited by polar discontinuity requirements.