First-principles simulations on the structural and energetic properties of domains in PbTiO₃/SrTiO₃ superlattices

2012/02/24 by Aguado-Puente, Pablo, Junquera, Javier
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)

paper · doi:10.48550/arxiv.1202.5481

Abstract

We report first-principles calculations, within the density functional theory, on the structural and energetic properties of 180^∘ stripe domains in (PbTiO₃)_n/(SrTiO₃)_n superlattices. For the explored periodicities (n=3 and 6) we find that the polydomain structures compete in energy with the monodomain phases. Our results suggest the progressive transition, as a function of n, from a strong to a weak electrostatic coupling regime between the SrTiO₃ and PbTiO₃ layers. Structurally, they display continuous rotation of polarization connecting 180^∘ domains. A large offset between [100] atomic rows across the domain wall and huge strain gradients are observed. The domain wall energy is very isotropic, depending very weakly on the stripe orientation.

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