Determination of Structural, Electronic, Optical and Mechanical Properties of Brookite TiO2 Using Various Exchange-Correlation

Abstract

This paper presents a study and analysis applicable to structural, electronic, optical and mechanical properties of one of rare variant of Titanium dioxide (TiO2) i.e. brookite using self-consistent Orthogonalized Linear Combination of Atomic Orbitals method (OLCAO) under the framework of Density Functional Theory (DFT). Structural, electronic and mechanical properties are investigated using Generalized Gradient Approximation (GGA) with Perdew-Burke-Ernzerhof (PBE), Perdew-Burke-Ernzerhof solid (PBES), Becke-Perdew86 (BP86), Perdew Wang91(PW91) and Becke88-Perdew Wang91 Correlation(BPW91) as exchange-correlation. Correlation of electronic and optical properties are performed using GGA-PBES and Meta-gga(MGGA)-Tran and Blaha(TB09). The observed data are match up with the previously reported computational as well as experimental data. Obtained lattice parameters using GGA-PBES, Bond length between Ti and O using PBE and BPW91, bandgap value using MGGA-TB09 and bulk modulus using PW91 and BPW91 matches very well with the experimental values. Comparision using GGA-PBES and MGGA- (TBO9) shows that calculated dielectric constant and refractive index as obtained using GGA-PBES are higher than MGGA approach and optical absorption for brookite TiO2 occurs in UV region while absorption spectrum using MGGA shifts the wavelength towards the lower energy band of EM spectrum.