Coulomb excitations in ABC-stacked trilayer graphene

The layer-based random-phase approximation is further developed to investigate electronic excitations in trilayer ABC-stacked graphene. All layer-dependent atomic interactions and Coulomb interactions are included in the dynamic charge screening. There exist rich and unique (momentum, frequency)-excitation phase diagrams, in which the complex single-particle excitations and five kinds of plasmon modes are dominated by unusual energy bands and doping carrier densities. The latter frequently experience significant Landau damping due to the former, leading to coexistence or destruction in the energy-loss spectra. Specifically, the dispersion of the only acoustic plasmon in the pristine case is dramatically changed from linear to square root, even at very low doping.