Optical properties of anatase and rutile TiO2 studied by GGA+U

TL;DR

This study uses GGA+U calculations to analyze the electronic and optical properties of anatase and rutile TiO2, successfully matching experimental data and comparing phase differences.

Contribution

It applies the GGA+U method to accurately reproduce TiO2's optical properties and compares electronic structures of anatase and rutile phases.

Findings

GGA+U reproduces experimental band gaps

Optical properties agree with experimental data

Differences in birefringence and anisotropy between phases

Abstract

The optical properties of thermally annealed TiO2 samples depend on their preparation process, and the TiO2 thin films usually exist in the form of anatase or rutile or the mixture of the two phases. The electronic structures and optical properties of anatase and rutile TiO2 are calculated by means of First-principles generalized gradient approximation (GGA) +U approach. By Introducing the Coulomb interactions on 3d orbitals of Ti atom (Ud) and 2p orbitals of O atom (Up), we can reproduce the experimental values of the band gap. The optical properties of anatase and rutile TiO2 are obtained by means of GGA+U method, well agreeing with experimental results and other theoretical data. Further we present the comparison of the electronic structure, birefringence and anisotropy between the two phases of TiO2.