Hyperbolic phonon-plasmon polaritons in a hBN-graphene van der Waals structure

In this paper, a thorough theoretical study of a class of collective excitations, dubbed hyperbolic surface phononplasmon polaritons, is performed. These types of light-matter excitations are shown to have unique properties that allow to explore them both as the basis of ultra-sensitive devices to the dielectric nature of their surroundings. The system is a van derWaals heterostructure-a layered metamaterial, composed of different2Dmaterials in direct contact one with another, namely, graphene ribbons and hexagonal boron nitride slabs of nanometric size. In the paper, we discuss the spectrum of these classes of excitations, the associated electromagnetic fields, the sensitivity to the dielectric function of its surroundings, and the absorption spectrum. All of this is accomplished using an analytical model that considerably diminishes the computational burden, as well as elucidates the underling physical mechanism of the excitations supported by the device.