First-principles study of the interplay between grain boundaries and domain walls in ferroelectric PbTiO3

Structures and energies of stoichiometric 3(111)[110], 3(112)[110], 5(201)[010], and 5(301)[010] symmetrical tilt grain boundaries are determined in the tetragonal ferroelectric PbTiO 3 using a combination of first-principles electronic-structure calculations and atomistic shell-model-potential simulations. The focus is on grain boundaries, which are ferroelectric domain walls at the same time. A main result is that it is energetically preferential for a 180° domain wall to reside in the region of a 5 grain boundary. This is interpreted as a more general mechanism for domain-wall pinning in polycrystalline ferroelectric materials.