Neutron scattering study of the high energy graphitic phonons in superconducting CaC${}_6$

Abstract

We present the results of a neutron scattering study of the high energy phonons in the superconducting graphite intercalation compound CaC${}_6$. The study was designed to address hitherto unexplored aspects of the lattice dynamics in CaC${}_6$, and in particular any renormalization of the out-of-plane and in-plane graphitic phonon modes. We present a detailed comparison between the data and the results of density functional theory (DFT). A description is given of the analysis methods developed to account for the highly-textured nature of the samples. The DFT calculations are shown to provide a good description of the general features of the experimental data. This is significant in light of a number of striking disagreements in the literature between other experiments and DFT on CaC${}_6$. The results presented here demonstrate that the disagreements are not due to any large inaccuracies in the calculated phonon frequencies.

5 pages, 4 figures, updated version with changes to figure 4 (Accepted in PRB)

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Cited by in corpus (4)

• Phonons in potassium doped graphene: the effects of electron-phonon interactions, dimensionality and ad-atom ordering
• Pressure-induced Superconductivity in CaC2
• Superconductivity in graphite intercalation compounds
• Comparative study of the phonons in non-superconducting BaC6 and superconducting CaC6 using inelastic x-ray scattering