Thermodynamics of Ferroelectric and Optical Properties in KNbO3

Fuente: arXiv
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Main Authors: Ross, Aiden, Gopalan, Venkatraman, Chen, Long-Qing
Format: Preprint
Published: 2026
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author Ross, Aiden
Gopalan, Venkatraman
Chen, Long-Qing
author_facet Ross, Aiden
Gopalan, Venkatraman
Chen, Long-Qing
contents Potassium niobate (KNbO3) is a prototypical perovskite ferroelectric with large electro-optic and nonlinear optical responses, high optical damage thresholds and a rich sequence of temperature-driven phase transformations, making it a promising platform for tunable photonic devices. In this work, we develop a thermodynamic model for the coupled ferroelectric and optical properties of KNbO3. By separating the total polarization into lattice and electronic contributions, the model provides a unified description of both the anisotropic ferroelectric and optical properties. The thermodynamic coefficients are determined by fitting to experimental measurements of the spontaneous polarization, dielectric susceptibilities, lattice parameters, and refractive indices. Without any further fitting, the model quantitatively predicts the temperature dependence of the electro-optic and piezoelectric coefficients in close agreement with experimental measurements. By utilizing the electronic polarization equation of motion, the model further captures the optical dispersion in the near infrared to visible spectrum. This work provides the thermodynamic foundation for future studies of coupled ferroelectric and optical phenomena in KNbO3.
format Preprint
id arxiv_https___arxiv_org_abs_2601_17150
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Thermodynamics of Ferroelectric and Optical Properties in KNbO3
Ross, Aiden
Gopalan, Venkatraman
Chen, Long-Qing
Materials Science
Potassium niobate (KNbO3) is a prototypical perovskite ferroelectric with large electro-optic and nonlinear optical responses, high optical damage thresholds and a rich sequence of temperature-driven phase transformations, making it a promising platform for tunable photonic devices. In this work, we develop a thermodynamic model for the coupled ferroelectric and optical properties of KNbO3. By separating the total polarization into lattice and electronic contributions, the model provides a unified description of both the anisotropic ferroelectric and optical properties. The thermodynamic coefficients are determined by fitting to experimental measurements of the spontaneous polarization, dielectric susceptibilities, lattice parameters, and refractive indices. Without any further fitting, the model quantitatively predicts the temperature dependence of the electro-optic and piezoelectric coefficients in close agreement with experimental measurements. By utilizing the electronic polarization equation of motion, the model further captures the optical dispersion in the near infrared to visible spectrum. This work provides the thermodynamic foundation for future studies of coupled ferroelectric and optical phenomena in KNbO3.
title Thermodynamics of Ferroelectric and Optical Properties in KNbO3
topic Materials Science
url https://arxiv.org/abs/2601.17150