Impact of 3D curvature on the polarization orientation in non-Ising domain walls

TL;DR

This study investigates how three-dimensional curvature influences the polarization structure of non-Ising domain walls in LiNbO3, revealing that curvature modulates polarization via flexoelectric effects and charge interactions.

Contribution

It provides new insights into the relationship between 3D curvature and polarization configurations in ferroelectric domain walls, highlighting the role of flexoelectricity and charge effects.

Findings

Curvature modulates the Nél-like polarization character.

Flexoelectric effect influences polarization variation.

Curved interfaces enable tailoring of nanoscale polar states.

Abstract

Ferroelectric domain boundaries are quasi-two-dimensional functional interfaces with high prospects for nanoelectronic applications. Despite their reduced dimensionality, they can exhibit complex non-Ising polarization configurations and unexpected physical properties. Here, the impact of the three-dimensional (3D) curvature on the polarization profile of nominally uncharged 180{\deg} domain walls in LiNbO3 is studied using second-harmonic generation microscopy and 3D polarimetry analysis. Correlations between the domain wall curvature and the variation of its internal polarization unfold in the form of modulations of the N\'eel-like character, which we attribute to the flexoelectric effect. While the N\'eel-like character originates mainly from the tilting of the domain wall, the internal polarization adjusts its orientation due to the synergetic upshot of dipolar and monopolar bound charges and their variation with the 3D curvature. Our results show that curved interfaces in solid crystals may offer a rich playground for tailoring nanoscale polar states.