Optical properties of anatase and rutile TiO${}_{2}$ studied by GGA + U ^*

Abstract

The optical properties of thermally annealed TiO 2 samples depend on their preparation process, and the TiO 2 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 TiO 2 are calculated by means of First-principles generalized gradient approximation (GGA) +U approach. By Introducing the Coulomb interactions on 3d orbitals of Ti atom (U d ) and 2p orbitals of O atom (U p ), we can reproduce the experimental values of the band gap. The optical properties of anatase and rutile TiO 2 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 TiO 2 .

Comparative study on structural, electronic, optical and mechanical properties of normal and high pressure phases titanium dioxide using DFT

“…Dielectric constant value for anatase and rutile using GGA-PBES are close to the experimental value [57,58]. Dielectric constant and refractive index calculated using MGGA-TBO9 for anatase and rutile are very much close to experimental data [40,41,59,60] and better than [26,37,38]. Elastic constat of rutile TiO 2 are in excellent agreement with experimental data [65].…”

“…Effective mass analysis of cubic TiO 2 shows that transfer rate is faster in pyrite and hence exhibits higher photocatalytic activity than fluorite. Dielectric constant value calculated using OLCAO-GGA-PBE-SOL for all the structure are higher than other theoretical data [6,23,26,32,38]. Dielectric constant value for anatase and rutile using GGA-PBES are close to the experimental value [57,58].…”

“…Researchers have calculated the structural, elastic, electronic, optical, thermal and acoustic properties of various phases of TiO 2 theoretically [6,23,25,26,29,[31][32][33][34][35][36][37][38] as well as experimentally [11,30,[39][40][41][42]. Zhang et al [43], analyzed the photocatalytic activity among natural phases of TiO 2 based on the comparison of effective masses for these polymorphs and found that anatase is having higher photocatalytic activity than other two polymorphs.…”

Rutile, anatase, brookite and titania thin film from Hubbard corrected and hybrid DFT

“…Combining separate U parameters for Ti 3d and O 2p electrons can improve the description of the atomic structure and in particular the electronic band gap [62]. However, it gives rise to additional complexity and inconsistencies, particularly with respect to the calculated optical response [55,56]. Very recently, Kirchner-Hall et al [63] performed an extensive benchmarking of DFT+U for various compounds, including R-TiO 2 and noted that the calculated band gaps are extremely sensitive to the type of projector functions.…”

Room temperature ferromagnetism in D–D neutron irradiated rutile TiO2 single crystals

“…The E g decreases gradually with the increase in uence. Based on our previous analysis and theoretical research, 14,45 V O , V Ti and V O -Ti 3+ defects introduce unpaired states in the band gap, which could narrow the band gap. As the uence increases, ever larger concentrations of defects and ever thicker defect states imply an ever narrower band gap.…”