Electronic structure and optical properties of prominent phases of $$\hbox {TiO}_{2}$$ TiO 2 : First-principles study

Abstract

First-principles study based on density functional theory (DFT) of two prominent phases, the rutile and the anatase phases, of titanium dioxide ( \(\hbox {TiO}_2\) ) are reported within the generalized gradient approximation (GGA). Our calculated band structure shows that there is a significant presence of O-2p and Ti-3d hybridization in the valence bands. These bands are well separated from the conduction bands by a direct band gap value of 1.73 eV in the rutile phase and an indirect band gap value of 2.03 eV in the anatase phase, from \(\Gamma \) to X. Our calculations reproduced the peaks in the conduction and valence band, are in good agreement with experimental observations. Our structural optimization for the rutile and anatase phase led to lattice parameter values of 4.62 Å and 2.99 Å rutile and 3.80 Å and 9.55 Å for anatase for a and c. The static dielectric values 7.0 and 5.1 for the rutile and anatase phases respectively are in excellent agreement with experimental results. Our calculation of optical properties reveals that maximum value of the transmittance in anatase phase of \(\hbox {TiO}_2\) may be achieved by considering the anisotropic behaviour of the optical spectra in the optical region for transparent conducting application.

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