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DF: Fachverband Dielektrische Festkörper

DF 4: Focused Session on Ferroic Domain Walls I (DF with MA)

DF 4.6: Vortrag

Montag, 16. März 2015, 17:20–17:40, EB 107

3D-mapping of ferroelectric domain walls by Cherenkov second-harmonic generation — •Thomas Kämpfe¹, Philipp Reichenbach¹, Mathias Schröder¹, Alexander Haußmann¹, Theo Woike², and Lukas M. Eng¹ — ¹Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Str. 1, 01069 Dresden, Germany — ²Institut für Strukturphysik, Technische Universität Dresden, Zellescher Weg 16, 01069 Dresden, Germany

Ferroelectric domain walls (DWs) are a novel approach towards nanoelectronic circuitry since providing localized conduction within a fully insulating host matrix. The key factor is the DW inclination angle α with respect to the crystallographic axes determining the amount of polarization charge at the head-to-head DWs. Hence, the conductivity can be considerably tuned via doping concentration and poling conditions. We apply Cherenkov second-harmonic generation (C-SHG) to map such charged DWs in three dimensions throughout a mm-thick Mg:LiNbO₃ single crystal [1]. We will present domain wall topologies for different cases, also including surface domains, which are created upon external UV illumination and exhibiting also tail-to-tail DWs. We investigated the domain wall protrusion upon different illumination strengths. Moreover, we will also introduce into an extended version of C-SHG based on interferometric SHG (I-SHG). I-SHG provides several advantages as compared to C-SHG, such as an increased vertical resolution, a larger vertical imaging range, as well as easier imaging conditions.
T. Kämpfe et al., Phys. Rev. B, 89, 035314 (2014).