Hyperbolic plasmons on uniaxial metamaterials

We analyze surface electromagnetic waves with hyperbolic dispersion supported at the interface between a semi-infinite isotropic medium and an effective uniaxial material. Apart from known types plasmons with hyperbolic dispersion curve, sometimes referred to as Dyakonov plasmons [Z. Jacob and E. E. Narimanov, APL 93, 221109 (2008)], we classify two new types of surface waves with hyperbolic dispersion. One type of such waves, in contrary to Dyakonov plasmons, does not require hyperbolic metamaterials to be involved. These hybrid-polarized plasmon modes with both TE and TM electromagnetic components are directional. Their propagation direction can be controlled by changing material parameters.