First-principles calculations and model analysis of plasmon excitations in graphene

Abstract

Plasmon excitations in free-standing graphene and graphene/hexagonal boron nitride (hBN) heterostructure are studied using linear-response time-dependent density functional theory within the random phase approximation. Within a single theoretical framework, we examine both the plasmon dispersion behavior and lifetime (line width) of Dirac and $\pi$ plasmons on an equal footing. Particular attention is paid to the influence of the hBN substrate and the anisotropic effect. Furthermore, a model-based analysis indicates that the correct dispersion behavior of $\pi$ plasmons should be ${\omega }_{\pi }(q)=\sqrt{E_g^2+\beta q}$ for small $q$'s, where $E_g$ is the band gap at the $M$ point in the Brillouin zone, and $\beta$ is a fitting parameter. This model is radically different from previous proposals, but in good agreement with our calculated results from first principles.

13 pages

References in corpus (11)

• Graphene plasmonics
• Dielectric function, screening, and plasmons in 2D graphene
• Graphene Plasmonics for Terahertz to Mid-Infrared Applications
• Dynamical polarization of graphene at finite doping
• Highly confined low-loss plasmons in graphene-boron nitride heterostructures
• Excitonic Effects on the Optical Response of Graphene and Bilayer Graphene
• The quasiparticle spectral function in doped graphene
• Plasmon losses due to electron-phonon scattering: the case of graphene encapsulated in hexagonal Boron Nitride
• First-Principles Study of Electron Linewidths in Graphene
• Electronic excitations in quasi-2D crystals: What theoretical quantities are relevant to experiment?
• Theoretical electron energy loss spectroscopy of isolated graphene