Structure and energetics of 180° domain walls in PbTiO3 by density functional theory

Abstract

Density functional theory at the level of the local density approximation withthe projector augmented wave method is used to determine the structure of180° domain walls intetragonal ferroelectric PbTiO3. In agreement with previous studies, it is found that PbO-centered {100} walls have lower energies thanTiO2-centered {100} walls, leading to a Peierls potential barrier for wall motion along⟨010⟩ of ∼ 36 mJ m − 2. In addition to the Ising-like polarization along the tetragonal axis, it is found thatnear the domain wall, there is a small polarization in the wall-normal directionaway from the domain wall. These Néel-like contributions to the domain wall areanalyzed in terms of the Landau–Ginzburg–Devonshire phenomenological theoryfor ferroelectrics. Similar characteristics are found for {110} domain walls, whereOO-centered walls are energetically more favorable than the PbTiO-centered walls.