Properties of the low-frequency phonon spectra of ferroelectric barium titanate-based heterostructures

TL;DR

This study investigates the low-frequency phonon spectra of ferroelectric barium titanate-based heterostructures using polarized Raman spectroscopy across a broad temperature range, revealing phase transitions and phonon mode coexistence.

Contribution

It provides new insights into the phonon spectra and phase transition behavior of BaTiO3-based heterostructures through detailed Raman analysis.

Findings

Identified phase transition temperatures in heterostructures.

Observed coexistence of Debye-type central peak and soft mode.

Mapped temperature-dependent phonon spectra in the sub-THz range.

Abstract

Polarized Raman spectra of the epitaxial Ba0.5Sr0.5TiO3 film, bi-color BaTiO3/Ba0.5Sr0.5TiO3 superlattice, and tri-color BaTiO3/Ba0.5Sr0.5TiO3/SrTiO3 superlattice were studied in a broad temperature range of 80-700 K. Based on the temperature dependence of the polar modes we determined the phase transitions temperatures in the studied heterostructures. In the sub-THz frequency range of the Y(XZ)Y spectra, we revealed the coexistence of the Debye-type central peak and soft mode in bi-color BaTiO3/Ba0.5Sr0.5TiO3 superlattice.