Zigzag charged domain walls in ferroelectric PbTiO3


Our study delved into a theoretical exploration of charged domain walls in ferroelectric PbTiO3, which were compensated by randomly distributed immobile charge defects located within a relatively broad slab. To achieve this, we employed a combination of atomistic shell-model simulations and continuous phase-field simulations based on the Ginzburg-Landau-Devonshire model. Our findings showed that domain walls form a zigzag pattern, and we examined their properties across a broad range of compensation-region widths, ranging from a few nanometers to over 100 nm, focusing in particular on understanding the zigzag modulation lengths in terms of material properties of PbTiO3. The zigzag formation is accompanied by a local ferroelectric-polarization rotation, which we proposed as an efficient mechanism for local charge compensation. Our study provides a new understanding of the behavior of charged domain walls in ferroelectric materials and highlights the significance of the considered compensation charges in their formation. The insights gained from our study may contribute to the development of advanced ferroelectric materials with applications in the field of smart-materials for electronics.

Schematic picture of the zigzag pattern and dependence of natural width of the zigzag triangles
Top panel: Schematic picture of the zigzag pattern, which is used in the derivation of natural width of triangles. Red and blue colors and arrows correspond here to positively and negatively oriented ferroelectric domains (with respect to the x axis). The color of the defects is red for positive and blue for negative point defects. Bottom panel: Dependence of natural width of the zigzag triangles. Bullets: Phase-field simulations with homogeneous compensation charge; the dashed line is just a connection of these. Crosses: Phase-field simulations with randomly distributed defect charges. Solid line: Simplified analytical model. Numerical and analytical approaches show an excellent corespondence for large thicknesses of the compensation-region L.  

Contact person: Pavel Marton