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The-electronic excitations are studied for the AA-and AB-stacked bilayer graphites within the linear self-consistent-field approach. They are strongly affected by the stacking sequence, the interlayer atomic interactions, the interlayer Coulomb interactions, and the magnitude of the transferred momentum. However, they hardly depend on the direction of the transferred momentum and the temperature. There are three lowfrequency plasmon modes in the AA-stacked system but not the AB-stacked system. The AA-and AB-stacked plasmons exhibit the similar plasmons. The first low-frequency plasmon behaves as an acoustic plasmon, and the others belong to optical plasmons. The bilayer graphites quite differ from the monolayer graphite and the AB-stacked bulk graphite, such as the low-frequency plasmons and the small-momentum plasmons.

In the presence of a perpendicular electric field, the low-energy electronic properties of the AB-stacked N-layer graphites with layer number N = 2, 3, and 4, respectively, are examined through the tight-binding model. The interlayer interactions, the number of layers, and the field strength are closely related to them. The interlayer interactions can significantly change the energy dispersions and produce new band-edge states. Bi-layer and four-layer graphites are two-dimensional semimetals due to a tiny overlap between the valence and conduction bands, while tri-layer graphite is a narrow-gap semiconductor. The electric field affects the low-energy electronic properties: the production of oscillating bands, the cause of subband (anti)crossing, the change in subband spacing, and the increase in band-edge states. Most importantly, the aforementioned effects are revealed completely in the density of states, e.g. the generation of special structures, the shift in peak position, the change in peak height, and the alteration of the band gap.

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