The excitation spectra of ABC-stacked graphene superlattices are calculated by the gradient approximation. Based on the selection rule, only excitations between the conduction and valence bands of the same pairs are allowed. These excitations occur at the critical points in the energy-wave vector space. Different polarization directions induce different spectra. The spectra of a parallel polarization are stronger than those of a vertical polarization. The strong electron-hole excitations cause special structures in the electron-hole excitation and reflectance spectra. However, only one plasmon peak exists in the loss spectra of the parallel polarization. Some properties are consistent with the experimental measurements.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)