First-principles calculations of a corrugated anatase TiO2 surface

The structural, electronic and optical properties of a corrugated anatase TiO2 surface are studied using the pseudopotential density-functional theory (DFT). The calculation of the electronic and optical properties provides the electronic and optical band gaps. The optical band gap is calculated using the photon energy dependent imaginary part of the dielectric function that indicates the exact optical transitions from occupied valence bands to unoccupied conduction bands. The estimated optical band gap is higher than the electronic band gap at the Γ point and shows consistency with the experimental band gap of an anatase TiO2 thin-film. This result also shows the significant optical anisotropy in directions normal and parallel to the corrugated surface.