Berlin 2018 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 6: Ferroelectric Domain Walls II (joint session KFM/TT)

KFM 6.8: Vortrag

Montag, 12. März 2018, 17:45–18:00, EMH 225

LiNbO3 thin-film crystals: A novel class of materials for domain engineering and enhanced domain wall conductivity — •Tillmann Stralka, Alexander Hausmann, Lukas Wehmeier, and Lukas M. Eng — Institute of Applied Physics, Technische Universität Dresden, Germany

In the last years, research on ferroelectric domain wall conductivity (DWC) mostly has focused either on PLD-grown, ultra-thin ferroelectric (FE) films [1] or FE bulk-single crystals [2,3,4]. Here we extend DWC to a novel and extremely prospective class of materials, i.e. free-standing thin-film crystals made up from ultra-thin single-crystalline LiNbO₃ (LNO) sheets. We use 5%-Mg-doped LNO polished down to a 22-µm thickness. Beyond high-voltage- [3] and super-bandgap-illumination-induced [4] DW engineering, the sample thinness also allows to write domain patterns by low-voltage AFM lithography, resulting in fully penetrating through domains. Of central interest in these thin-film LNO crystals is the mutual interaction between neighboring DWs, hence providing a novel tool for DW shape engineering on the very local length scale. Investigations are carried out using a combination of AFM techniques (PFM, c-AFM, topography) and Cerenkov Second Harmonic Microscopy [5], as well as by monitoring the electrical transport in DWs along the crystallographic X and Y axes in LNO.
J. Seidel et al., Nature Mater. 8 (2009) 229. [2] T. Sluka et al., Nature Comm. 4 (2013) 1808. [3] C. Godau et al., ACS Nano 11 (2017) 4816. [4] M. Schröder et al., Adv. Func. Mater. 22 (2012) 3926. [6] L. Wehmeier et al., Phys. Stat. Solidi 11 (2017) 1700267.