Acoustic plasmons and composite hole-acoustic plasmon satellite bands in graphene on a metal gate

We demonstrate that single-layer graphene in the presence of a metal gate displays a gapless collective (plasmon) mode that has a linear dispersion at long wavelengths. We calculate exactly the acoustic-plasmon group velocity at the level of the random phase approximation and carry out microscopic calculations of the one-body spectral function of such systems. Despite screening exerted by the metal, we find that graphene’s quasiparticle spectrum displays a very rich structure characterized by composite hole-acoustic plasmon satellite bands (that we term for brevity “soundarons”), which can be observed by e.g. angle-resolved photoemission spectroscopy.

► We consider single-layer graphene in the presence of a metal gate.
► It displays a plasmon mode that has a linear dispersion at long wavelengths.
► We calculate exactly the acoustic-plasmon group velocity at the level of the RPA.
► We carry out microscopic calculations of the one-body spectral function.
► Quasiparticle spectrum displays a rich structure characterized by hole-acoustic plasmon satellite bands.