Short wavelength collective excitations in graphite intercalate C₃₆Cs

Abstract

Molecular dynamics simulations, of the stage-3 caesium intercalated graphite using a simple analytical potential, show evidence of discrete excitations at wavevectors well beyond the first Brillouin zone for the mean Cs-Cs repeat distance—the phenomenon found experimentally in stage-2 rubidium intercalated graphite (Kamitakara, W. A., and Zabel, H., 1985, Phys. Rev. B, 32, 7817). The model also predicts a gap in the dispersion curve for longitudinal density fluctuations at the first structure factor maximum and modulations at higher maxima similar to those found in three-dimensional liquid metals.