Tailoring the plasmonic properties of ultrathin TiN films at metal-dielectric interfaces [Invited]

The optical properties of a TiN/(Al,Sc)N superstructures deposited on MgO substrates are studied by using first principles approaches. The modifications of the plasmonic response of ultrathin TiN layers when faced to MgO and nitride surfaces are interpreted at the microscopic level, in terms of the electronic structure of the TiN/dielectric interfaces. The hyperbolic behavior of the multi-stacked metamaterial, described both via the effective medium theory and first principles simulations of periodic TiN/(Al,Sc)N superlattices, is closely investigated and directly compared to recent experimental results. The latter comparison underlines the crucial role of quantum confinement especially for the ultrathin dielectric layers. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement