First-principles calculations of $LiNbO_3$ optical properties: from far-infrared to ultraviolet

TL;DR

This study uses first-principles density functional theory calculations to analyze the optical properties of ferroelectric LiNbO3 across a broad spectrum from far-infrared to ultraviolet, comparing different computational approaches.

Contribution

It demonstrates that hybrid PBESOL0 functional provides a more accurate description of LiNbO3's optical properties than the GGA PBESOL functional.

Findings

Hybrid PBESOL0 functional aligns better with experimental data.

Calculated dielectric and optical properties cover a wide spectral range.

Atomic-orbital all-electron Gaussian basis sets are effective for such calculations.

Abstract

We perform first-principles calculations of optical properties for ferroelectric phase of $LiNbO_3$ crystal using density functional theory for wide range of wavelengths, from far-infrared to ultraviolet. We study frequency dependence of complex dielectric tensor and related quantities, such as refractive and reflection indices, absorption coefficients, etc. Our calculation incorporate advantages of numerical approaches based on atomic-orbital all-electron Gaussian-type basis sets, as it is realized in CRYSTAL14 program. We compared predictions obtained in general-gradient approach with PBESOL exchange-correlation functional and in hybrid approach with PBESOL0 functional, and we have found that hybrid PBESOL0 functional is more applicable to describe the wide set of the experimental data.