  Electronic Coulomb excitations in monolayer silicene are investigated by
using the Lindhard dielectric function and a newly developed generalized
tight-binding model (G-TBM). G-TBM simultaneously contains the atomic
interactions, the spin-orbit coupling, the Coulomb interactions, and the
various external fields at an arbitrary chemical potential. We exhibit the
calculation results of the electrically tunable magnetoplasmons and the strong
magnetic field modulation of plasmon behaviors. The two intriguing phenomena
are well explained by determining the dominant transition channels in the
dielectric function and through understanding the electron behavior under the
multiple interactions (intrinsic and external). A further tunability of the
plasmon features is demonstrated with the momentum transfer and the Fermi
energy. The methodological strategy could be extended to several other 2D
materials like germanene and stanene, and might open a pathway to search a
better system in nanoplasmonic applications.
