Phase-field modeling and electronic structural analysis of flexoelectric effect at 180{\deg} domain walls in ferroelectric PbTiO3

摘要

Flexoelectric effect is the coupling between strain, polarization and theirgradients, which are prominent at the nanoscale. Although this effect isimportant to understand nanostructures, such as domain walls in ferroelectrics,its electronic mechanism is not clear. In this work, we combined phase-fieldsimulations and first-principles calculations to study the 180{\deg} domainwalls in tetragonal ferroelectric PbTiO3, and found that the ultimate source ofN\'eel components is the gradient of the square of spontaneous polarizations.Electronic structural analysis reveals that there is a redistribution ofelectronic charge density and potential around domain walls, which produces theelectric field and N\'eel components. This work thus sheds light on theelectronic mechanism of the flexoelectric effect around 180{\deg} domain wallsin tetragonal ferroelectrics.