Modeling Temperature, Frequency, and Strain Effects on the Linear Electro-Optic Coefficients of Ferroelectric Oxides

TL;DR

This paper introduces a semi-empirical approach combining first-principles calculations and phenomenological modeling to predict how temperature, frequency, and strain affect the electro-optic coefficients of ferroelectric oxides, aiding material design.

Contribution

It develops a novel semi-empirical method to accurately compute electro-optic coefficients considering external effects, validated on key ferroelectric materials.

Findings

Predicted electro-optic constants align with experimental data.

The method provides temperature-, frequency-, and strain-dependent electro-optic tensors.

Benchmarks established for future experimental verification.

Abstract

An electro-optic modulator offers the function of modulating the propagation of light in a material with electric field and enables seamless connection between electronics-based computing and photonics-based communication. The search for materials with large electro-optic coefficients and low optical loss is critical to increase the efficiency and minimize the size of electro-optic devices. We present a semi-empirical method to compute the electro-optic coefficients of ferroelectric materials by combining first-principles density-functional theory calculations with Landau-Devonshire phenomenological modeling. We apply the method to study the electro-optic constants, also called Pockels coefficients, of three paradigmatic ferroelectric oxides: BaTiO3, LiNbO3, and LiTaO3. We present their temperature-, frequency- and strain-dependent electro-optic tensors calculated using our method. The predicted electro-optic constants agree with the experimental results, where available, and provide benchmarks for experimental verification.