Interfacial Polarization and Pyroelectricity in Antiferrodistortive Structures Induced by a Flexoelectric Effect and Rotostriction

TL;DR

This paper theoretically demonstrates that the combined flexoelectric and rotostriction effects can induce significant spontaneous polarization and pyroelectricity at interfaces and boundaries in non-ferroelectric perovskites, expanding understanding of their interfacial properties.

Contribution

It introduces a theoretical framework showing how flexoelectricity and rotostriction jointly induce polarization in non-ferroelectric perovskites near structural boundaries.

Findings

Large spontaneous polarization (~1-5 μC/cm²) at SrTiO₃ boundaries.

Polarization appears below the antiferrodistortive transition temperature (~105 K).

The effect is driven by interfacial flexoelectricity and rotostriction coupling.

Abstract

Theoretical analysis based on the Landau-Ginzburg-Devonshire (LGD) theory is used to show that the product effect of flexoelectricity and rotostriction can lead to a spontaneous polarization in the vicinity of antiphase boundaries, ferroelastic twin walls, surfaces and interfaces in the octahedrally tilted phase of otherwise non-ferroelectric perovskites such as CaTiO3, SrTiO3, and EuTiO3. As an example, we numerically demonstrate a large spontaneous polarization on the order of 1-5muC/cm2 at the SrTiO3 antidistortive phase boundaries at temperatures lower than the antiferrodistortive structural phase transition temperature of ~105 K