Interplay of couplings between antiferrodistortive, ferroelectric, and strain degrees of freedom in monodomain PbTiO3/SrTiO3 superlattices

Pablo Aguado-Puente*, Pablo García-Fernández, Javier Junquera

*Corresponding author for this work

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

We report first-principles calculations on the coupling between epitaxial strain, polarization, and oxygen octahedra rotations in monodomain (PbTiO 3)n/(SrTiO3)n superlattices. We show how the interplay between (i)the epitaxial strain and (ii)the electrostatic conditions can be used to control the orientation of the main axis of the system. The electrostatic constrains at the interface facilitate the polarization rotation and, as a consequence, we predict large piezoelectric responses at epitaxial strains smaller than those required considering only strain effects. In addition, ferroelectric (FE) and antiferrodistortive (AFD) modes are strongly coupled. Usual steric arguments cannot explain this coupling and a covalent model is proposed to account for it. The energy gain due to the FE-AFD coupling decreases with the periodicity of the superlattice, becoming negligible for n3.

Original languageEnglish
Article number217601
JournalPhysical Review Letters
Volume107
Issue number21
DOIs
Publication statusPublished - 15 Nov 2011
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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