Nanoscale piezoelectric response across a single antiparallel ferroelectric domain wall

Abstract

Surprising asymmetry in the local electromechanical response across a single antiparallel ferroelectric domain wall is reported. Piezoelectric force microscopy is used to investigate both the in-plane and out-of-plane electromechanical signals around domain walls in congruent and near-stoichiometric lithium niobate. The observed asymmetry is shown to have a strong correlation to crystal stoichiometry, suggesting defect-domain wall interactions. A defect-dipole model is proposed. Finite element method is used to simulate the electromechanical processes at the wall and reconstruct the images. For the near-stoichiometric composition, good agreement is found in both form and magnitude. Some discrepancy remains between the experimental and modeling widths of the imaged effects across a wall. This is analyzed from the perspective of possible electrostatic contributions to the imaging process, as well as local changes in the material properties in the vicinity of the wall.

Quantitative analysis of ferroelectric domain imaging with piezoresponse force microscopy

“…1 have already been reported [11,16,17]. For their explanation the excitation of resonant modes of the cantilever was proposed, tip and sample surface being in contact with each other.…”

Lateral signals in piezoresponse force microscopy at domain boundaries of ferroelectric crystals

“…[6][7][8] This slope originates from the opposed piezoelectric deformation of the crystal left and right from the tip when it is located on top of a domain boundary. To determine the angle α of the slope, the appropriate piezoelectric tensor element of the crystal d ij and the voltage U applied to the tip is needed.…”

“…5 But also at the domain boundaries a distinct lateral signal was occasionally observed. [6][7][8][9][10] The origin of this lateral signal at the domain boundaries (LS db ) is still under discussion. In this contribution we review the mechanisms proposed, compare them to our experimental results, and outline the complexity of the situation.…”

“…[8] strong friction between tip and sample surface seems to be assumed since the torsion of the cantilever is drawn as if the tip was taken along by the surface (Fig. 1(b)).…”

Asymptotic Effective Piezoelectric Coefficient Solution of Piezoresponse Force Microscopy for a Transversely Isotropic Piezoelectric Film

“…The decoupled approach neglects the electromechanical couplings and treats the piezoelectric strain as an eigenstrain. By doing that, the analysis becomes rather simple and is widely used to investigate PFM responses [9][10][11][12][13].…”