Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 14: Ferroics – Domains and Domain Walls 1

KFM 14.1: Vortrag

Mittwoch, 7. September 2022, 09:30–09:50, H5

Strain driven conducting domain walls in a Mott insulator — •Lukas Puntigam¹, Donald Evans¹, Markus Altthaler¹, Somnath Ghara¹, Lilian Prodan¹, Vladimir Tsurkan^1,2, Stephan Krohns¹, and Istvan Kezsmarki¹ — ¹Universität Augsburg, 86159, Augsburg, Deutschland — ²Institute of Applied Physics, MD 2028 Chisinau, Moldova

Ferroelectric domain walls, which can be written, tuned or erased, are being considered as functional building blocks for nanoelectronics. Especially, conducting domain walls are of high interest to achieve this functionality. To date, the origin for increased conductivity in ferroelectrics domain walls has been typically attributed to the formation of screening charges driven by polar discontinuities.

Here, we establish that for the template system, the lacunar spinel GaV₄S₈ also strain can enhance the conductivity of specific domain walls. This system exhibits ferroelectric domain pattern below a Jahn-Teller transition at 42K. At this temperature a change in its crystal structure can result in mechanical stress at domain walls. Piezoresponse force microscopy revealed an interesting ferroelectric pattern. Each ferroelectric domain can be identified by structural considerations to be one of the four possible polar direction. In case of domain walls between structural incompatible domains measurements with conductive atomic force microscopy show strongly enhanced conductivity denoting an additional twist highly conductive domain walls. Further, spatially resolved IV spectroscopy enable the investigation of the underlying conductivity mechanism at the tip-sample interface.