Dresden 2017 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 8: Ferroics - Domains, Domain Walls and Skyrmions I

DF 8.8: Vortrag

Dienstag, 21. März 2017, 11:45–12:00, WIL B321

Anisotropic domain wall conductivity (DWC) of neighboring 180^∘ DWs in LiNbO₃ single crystals — •Shuyu Xiao^1,2, Thomas Kaempfe², Yaming Jin¹, Alexander Haussman², Xiaomei Lu¹, and Lukas Eng² — ¹Physics School, Nanjing University, 210093 Nanjing, P. R. China — ²Institute of Applied Physics, Technical University of Dresden, George-Baehr-Strasse 1, Dresden, Germany

Investigating the origin and nature of the domain wall conductivity (DWC) in different ferroelectric materials such as BiFeO₃ [1], ErMnO₃ [2] and LiNbO₃ (LNO) [3] is of a major scientific interest today. Here, we report on anisotropic DWC, as found between neighboring head-to-head (h2h) and tail-to-tail (t2t) 180^∘ DWs in z-cut LNO single crystals. We applied conductive atomic force microscopy (cAFM) to quantify the local DW currents, probed the local polarization by piezo-response force microscopy (PFM), and mapped the 3D domain topology via Cherenkov Second Harmonic Generation (CSHG) microscopy [4]. The origin of the different DWC between h2h and t2t is studied by both phenomenological theories and dipole modelling assuming a quantum-mechanical tunneling process for electron transport. The domain wall inclination is found to account for the different conductivities in neighboring 180^∘ DWs, while the material symmetry determines whether h2h or t2t DW becomes more conductive. In addition, domain wall roughness plays an important role in DWC as well.

[1] J. Seidel et al., Nat. Mater., 8 (2009), 229 [2] D. Meier et al., Nat, Mater., 11 (2012), 284 [3] M. Schroeder et al., Mater. Res. Express., 1 (2014), 035012 [4] T. Kaempfe et al., Phys. Rev. B, 89 (2014), 035314