Material and Manufacturing Directorate, Air Force Research Laboratory Wright Patterson Air Force Base United States
Prediction of the frequency-dependent dielectric function of thin films poses computational challenges, and at the same time experimental characterization by spectroscopic ellipsometry remains difficult to interpret because of changes in stoichiometry and surface morphology, temperature, thickness of the film, or substrate. In this work, we report calculations for titanium nitride TiN, a promising material for plasmonic applications because of less loss and other practical advantages compared to noble metals. We investigated structural, electronic, and optical properties of stoichiometric bulk TiN, as well as of the TiN100, TiN110, and TiN111 outermost surfaces. Density functional theory DFT and many-body GW methods Greens G function-based approximation with screened Coulomb interaction W were used, ranging from G0W0, GW0 to partially self-consistent sc-GW0, as well as the GW-BSE Bethe-Salpeter equation and time-dependent DFT TDDFT methods for prediction of the optical properties. Structural parameters and the band structure for bulk TiN were shown to be consistent with previous work. Calculated dielectric functions, plasma frequencies, reflectivity, and the electron energy loss spectrum demonstrated consistency with experiment at the GW0-BSE level.
OSTP Journal Article
Journal of Applied Physics , 118, 01 Jan 0001, 01 Jan 0001,