Plasmon Dynamics in Electron-Doped Graphene and AA- versus AB-Stacked Bilayer Graphene

This study investigates low-frequency plasmons and single-particle excitations (SPEs) in monolayer and bilayer graphene with various stacking configurations. The dynamics of wave propagation under different time-dependent perturbation scenarios are elucidated using the random-phase approximation dielectric function and tight-binding Hamiltonian. The modulation of coherent excitations, particularly affecting plasmon waves, provides insights into the spatial and temporal dynamics on graphene sheets. A 2D acoustic plasmon mode is observed in monolayer graphene under extrinsic doping effects, while in bilayer graphene, it is accompanied by higher frequency optical plasmons. The predicted dynamic behavior, indicative of plasmon resonance, SPEs, and Landau damping with respect to stacking and doping effects, can be detected through ultrafast coherent dynamics observed via nanoimaging and nanospectroscopy techniques.