Electro-optic properties of ZrO2, HfO2 and LiNbO3 ferroelectric phases: A comprehensive and comparative study with density functional theory

TL;DR

This study uses density functional theory to compare the electro-optic properties of ZrO2, HfO2, and LiNbO3, revealing the dominant ionic contributions and phase-dependent behaviors in their Pockels effects.

Contribution

It provides a comprehensive computational comparison of the electro-optic properties of multiple ferroelectric phases using DFT, highlighting phase-specific ionic contributions.

Findings

Ionic contributions dominate the electro-optic coefficients in certain phases.

Low-frequency phonon modes significantly influence the Pockels effect.

Rhombohedral phases show zero ionic contribution to Pockels coefficients.

Abstract

We report the Pockels electro-optic properties of ZrO2 and HfO2 orthorhombic Pbc21 and rhombohedral R3m ferroelectric phases, and we compare them to the well-known LiNbO3 Pockels material from density functional theory calculations using the CRYSTAL suite of programs. Specifically, three essential processes are explicitly investigated: The electronic, the ionic (or vibrational), and the piezoelectric contributions. Our calculations reveal that the ionic part coming from the low frequency phonon modes contributes the most to the electro-optic coefficients of rhombohedral LiNbO3 and of orthorhombic ZrO2 and HfO2. While these low-frequency modes show zero contribution to Pockels coefficients for the rhombohedral phase of the latter compounds.