ABSTRACT
Bilayer silicene systems, corresponding to the AB stacking configurations, are revealed in the experimental growth; furthermore, there exist the AB-bt and AB-bb stable bucklings. The important differences between an AA-bt bilayer silicene and a monolayer silicene/graphene in the essential physical properties are thoroughly investigated through the viewpoint of valley structures in electronic energy spectra. An AA-bt bilayer silicene exhibits the unusual electronic properties, in sharp contrast with those of a single-layer silicene and an AA-stacked bilayer graphene, such as, energy bands and density of states. As to the AA-bt bilayer system, the optical gap, which is related to the constant-energy valence and conduction loops, quickly grow in the increment of gate voltage. Furthermore, its absorption intensity also behaves the monotonous enhancement. Apparently, the low-energy magneto-electronic states in the AA-bt bilayer silicene are responsible for the other essential physical properties, such as, the delta-function-like van Hove singularities, magneto-optical absorption spectra/selection rules, quantum Hall transports, and Inter-Landau-level dampings and magnetoplasmon modes.
