Photoinduced Domain Pattern Transformation in Ferroelectric/Dielectric Superlattices

TL;DR

This study demonstrates that above-bandgap optical excitation can induce reversible transformations in ferroelectric/dielectric superlattice domain patterns, driven by charge carrier trapping and screening effects, with observable lattice changes.

Contribution

It introduces a new understanding of photoinduced domain pattern transformation in ferroelectric superlattices, combining experimental X-ray scattering and theoretical modeling.

Findings

Domain pattern transforms to uniform polarization under optical excitation

Transformation involves charge carrier trapping and screening

Lattice expansion correlates with domain disappearance

Abstract

The nanodomain pattern in ferroelectric/dielectric superlattices transforms to a uniform polarization state under above-bandgap optical excitation. X-ray scattering reveals a disappearance of domain diffuse scattering and an expansion of the lattice. The reappearance of the domain pattern occurs over a period of seconds at room temperature, suggesting a transformation mechanism in which charge carriers in long-lived trap states screen the depolarization field. A Landau-Ginzburg-Devonshire model predicts changes in lattice parameter and a critical carrier concentration for the transformation.