Layer-enriched optical spectra of AB-stacked multilayer graphene

The band structures and optical properties of AB-stacked multilayer graphene are calculated using the tight-binding model and gradient approximation. For n_L-layer AB-stacked graphene, there are n²_L excitation channels at both the low and middle frequencies. However, in the excitation spectra, n_L (n_L - 1) peaks exist at the low frequency for even-layer (odd-layer) systems, and one-shoulder and nL peaks at the middle frequency. With increasing nL, the differences in the spectra between the odd and even layers are reduced. When n_L increases to 30 (50), the spectra of 2D and 3D systems are almost identical at the middle (low) frequency.