Plasmons and The Spectral Function of Graphene

We report on a theoretical study of the influence of electron-electron interactions on the one-particle Green's function of a doped graphene sheet based on the random-phase-approximation and on graphene's massless Dirac equation continuum model. We find that states near the Dirac point interact strongly with plasmons with a characteristic frequency $\omega^\star_{\rm pl}$ that scales with the sheet's Fermi energy and depends on its interaction coupling constant $\alpha_{\rm gr}$, partially explaining prominent features of recent ARPES data.