Spectroscopic mapping of local structural distortions in ferroelectric PbTiO3/SrTiO3 superlattices at the unit-cell scale

TL;DR

This study uses advanced electron spectroscopy and imaging to map local structural distortions at the unit-cell level in ferroelectric PbTiO3/SrTiO3 superlattices, revealing inhomogeneous polarization profiles.

Contribution

It introduces a high-resolution spectroscopic method to analyze local structural variations and polarization in ferroelectric superlattices at the atomic scale.

Findings

Identified local structural variations at interfaces with unit cell resolution.

Provided evidence for inhomogeneous polarization profiles.

Linked structural distortions to polarization behavior in superlattices.

Abstract

The local structural distortions in polydomain ferroelectric PbTiO3/SrTiO3 superlattices are investigated by means of high spatial and energy resolution electron energy loss spectroscopy combined with high angle annular dark field imaging. Local structural variations across the interfaces have been identified with unit cell resolution through the analysis of the energy loss near edge structure of the Ti-L2,3 and O-K edges. Ab-initio and multiplet calculations of the Ti-L2,3 edges provide unambiguous evidence for an inhomogeneous polarization profile associated with the observed structural distortions across the superlattice.