Investigation of Optical Spectrum Properties of Hexagonal Boron Nitride from Metal to Dielectric Transition

Hexagonal boron nitride as a natural hyperbolic material has attracted lots of attention recently. Here, we investigate numerically the optical spectrum properties of hexagonal boron nitride from the perspective of optical transition. After careful data analysis, hexagonal boron nitride at the epsilon-near-zero point of permittivity either turns from a hyperbolic material to an effective dielectric for transverse magnetic-polarized wave or from an effective metal to an effective dielectric for transverse electric-polarized wave. The results in this work may pave the way for potential applications of hexagonal boron nitride in the field of metamaterials.