Electronic and optical properties of TiN$_{\mathrm{x}}$ from first-principles calculations

We present a systematic study of the structural, electronic and optical properties of bulk phases of TiN$_{\mathrm{x}}$ and its (111) surface for mimicking thin films, which are of interest technological in applications such as coatings. Time-dependent density functional theory and the GW approximation have been applied. In the first stage, a comparison between experimental ellipsometry data and the calculated optical absorption spectra, for example, for a surface upon changing stoichiometry, has been undertaken. The results demonstrate applicability of the methods in prediction of optical excitations for titanium nitride thin film, deposited with varying nitrogen flow rates.