Regensburg 2016 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 8: Focus Session: Ferroic Domain Walls II

DF 8.5: Talk

Tuesday, March 8, 2016, 15:20–15:40, H25

Enhancing the domain wall conductivity in lithium niobate single crystals — •Christian Godau, Thomas Kämpfe, Andreas Thiessen, Alexander Haußmann, and Lukas Eng — Institute of Applied Physics, Technische Universität Dresden, D-01062 Dresden, Germany

Highly conductive ferroelectric domain walls (DWs) were found for thin films [1] as well as single crystals [2]. In lithium niobate (LNO) this effect was forecast by theoretical considerations [3]. However, such a high conductivity has so far only been reported under support super band-gap illumination [4]. We show here that high voltage treatment of domain walls in bulk lithium niobate single crystals when applying voltage ramps of up to 1 kV to macroscopic electrodes, results in the desired high conductivity as well. An increase in domain wall conduction of several orders of magnitude can then be measured. High voltage treatment also affects the 3-dimensional domain wall shape, which was complementary delineated Cerenkov second harmonic generation (C-SHG) [5]. As a result, we are able to correlate the local domain wall conductive paths (measured by cAFM) to the DW inclination angle as deduced by C-SHG.

[1] J. Seidel et al., Nat. Mater. 8, 229 (2009)

[2] T. Sluka et al., Nat. Comm. 4, 1808 (2013)

[3] E. A. Eliseev et al., Phys. Rev. B 83, 235313 (2011)

[4] M. Schroeder et al., Adv. Funct. Mater. 22, 3926 (2012)

[5] T. Kämpfe et al., Phys. Rev. B 89, 035314 (2014)