Density functional theory at the level of the local density approximation with the projector augmented wave method is used to determine the structure of 180° domain walls in tetragonal ferroelectric PbTiO(3). In agreement with previous studies, it is found that PbO-centered {100} walls have lower energies than TiO(2)-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 that near the domain wall, there is a small polarization in the wall-normal direction away from the domain wall. These Néel-like contributions to the domain wall are analyzed in terms of the Landau-Ginzburg-Devonshire phenomenological theory for ferroelectrics. Similar characteristics are found for {110} domain walls, where OO-centered walls are energetically more favorable than the PbTiO-centered walls.
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