Abstract
In this letter we obtain the finite-temperature structure of 180° domain walls in PbTiO3 using a quasi-harmonic–lattice dynamics approach. We obtain the temperature dependence of the atomic structure of domain walls from 0 K up to room temperature. We also show that both Pb-centered and Ti-centered 180° domain walls are thicker at room temperature; domain wall thickness at T=300 K is about three times larger than that of T=0 K. Our calculations show that Ti-centered domain walls have a lower free energy than Pb-centered domain walls and hence are more likely to be seen at finite temperatures.