Strain-induced isosymmetric ferri-to-ferroelectric transition with large piezoelectricity

Abstract

We identify a first-order, isosymmetric transition between a ferrielectric (FiE) and ferroelectric (FE) state in $A$-site ordered LaScO${}_3$/BiScO${}_3$ and LaInO${}_3$/BiInO${}_3$ superlattices. Such a previously unreported ferroic transition is driven by the easy switching of cation displacements without changing the overall polarization direction or crystallographic symmetry. Epitaxial strains less than 2% are predicted to be sufficient to transverse the phase boundary, across which we capture a ~5X increase in electric polarization. In a fashion similar to classic Pb-based perovskite ceramics with a morphotropic phase boundary (MPB), we predict a large electromechanical response up to 131 pC/N in the vicinity of FiE-FE phase boundary. We propose this transition as alternative ferroic transition to obtain large piezoelectricity, with the additional advantage of operating under extreme conditions in benign chemistries and without chemical disorder.

arXiv comment7 pages, 6 figures, 2 Tables; Supplemental information available upon request