First-principle modelling of the ferroelectric switching in BaTiO3: concurrent switching versus domain wall motion

The ferroelectric switching phenomenon has been investigated on a BaTiO3 supercell in the tetragonal state using a first-principles density functional theory. The study shows that a consecutive reversal of polarization via switching of adjacent elementary unit cells is energetically more favourable than the single domain switching. The results thus explain the energetic rationality for the domain wall formation in an ideal structure without the presence of any microscopic non-uniformity. The analysis of individual domain wall energy densities suggests that it is not a constant quantity. The coercive field values for switching different domains have been computed, which identifies the nucleation and propagation phases of domain wall motion.