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

Abstract

In piezoresponse force microscopy a lateral signal at the domain boundaries is occasionally observed. In recent years, a couple of experiments have been reported and varying explanations for the origin of this lateral signal have been proposed. Additionally, elaborated theoretical modeling for this particular issue has been carried out. Here we present experimental data obtained on different crystallographic cuts of LiNbO 3 , BaTiO 3 , and KTiOPO 4 single crystals. We could thereby rule out some of the explanations proposed so far, introduce another possible mechanism, and quantitatively compare our results to the existing modeling.

Non-piezoelectric effects in piezoresponse force microscopy

“…1(c)), yields information on the vertical (lateral) component of the polarization, an approach referred to as vertical (lateral) PFM. [47,48] On the basis of the operational mechanism, vertical and lateral PFMs can provide profound insight into nanoscale ferro/piezoelectric phenomena such as piezoelectricity, [49][50][51][52] polarization switching dynamics, [53][54][55][56] domain growth, and wall motions. [57][58][59][60] Three-dimensional domain structures can also be explored by combining vertical and lateral PFMs.…”

Origin of piezoelectric response under a biased scanning probe microscopy tip across a 180∘ferroelectric domain wall

“…1(b)) is correct. However, the origin of the sample shear is more complex than assumed before and is dominated by the piezoelectric coefficient d 15 , instead of those proposed in the past expansion/contraction models (d 33 and d 31 ) [39][40][41] . The work also predicts two types of lateral signals (which are later labelled as 0° and 90° lateral PFM signals), the latter of which was not theoretically predicted before, and hence the only experiments 13 to show this signal were dismissed as an artefact.…”

“…In addition to FEM simulation, a revised analytical theory is now presented which predicts this signal. We also propose an averaging method for all the PFM signals over a finite contact area of the tip on the sample surface, which resolves the lineshape arguments raised by Soergel 41 and leads to the best agreement of the PFM line-shapes across domain walls between theory, simulation and experiments.…”

“…In comparison to the vertical PFM, the lateral PFM is not completely understood both theoretically and experimentally [39][40][41][42] . Lateral PFM refers to the lateral or sideways twisting of the PFM tip due to the sample piezoelectric displacements.…”

“…1). Jungk and Soergel argued against the slope model and instead proposed a model based on local electric field arising from the surface polarization charge near domain walls 42 , but later ruled out this claim 41 . Paruch et al 39,40 by showing that a shear model ( Fig.…”