Epitaxial superlattices with titanium nitride as a plasmonic component for optical hyperbolic metamaterials

Plasmonic and metamaterial devices require high-performance material building blocks, both plasmonic and dielectric, to be useful in any real-world application. Here, we develop both plasmonic and dielectric materials that can be grown epitaxially into ultrathin and ultrasmooth layers with sharp interfaces. We show that a superlattice consisting of titanium nitride as a plasmonic component behaves as an optical hyperbolic metamaterial and exhibits extremely high photonic density of states.