Plasmons in anisotropic Dirac systems

We consider the plasmon excitations in anisotropic two-dimensional Dirac systems, be it either anisotropic graphene or surfaces of topological insulators. Generalizing the exact density-density response function one finds a plasmon dispersion that is anisotropic already at the lowest frequencies. Asymptotic expressions are obtained for the dispersion in this regime. We show that the plasmon properties of the complete material class of anisotropic Dirac systems are characterized by just two dimensionless material parameters. The strong anisotropy can be used to guide the plasmon modes, introducing new functionalities to the field of Dirac plasmonics.

Automated summary

The study reveals that plasmon excitations in anisotropic two-dimensional Dirac systems exhibit anisotropy even at the lowest frequencies, with their properties characterized by two dimensionless material parameters. This strong anisotropy can guide plasmon modes and bring new functionalities to the field of Dirac plasmonics.