The pressure effect on the superconducting transition temperature (Tc) of the newly-discovered Ca-intercalated graphite compound CaC6 has been investigated up to ∼ 16 kbar. Tc is found to increase under pressure with a large relative ratio ΔTc/Tc of ≈ +0.4 %/kbar. Using first-principles calculations, we show that the large and positive effect of pressure on Tc can be explained in the scope of electron-phonon theory due to the presence of a soft phonon branch associated to in-plane vibrations of Ca atoms. Implications of the present findings on the current debate about the superconducting mechanism in graphite intercalation compounds are discussed.
@article{arxiv.cond-mat/0603530,
title = {Effect of Pressure on Superconducting Ca-intercalated Graphite CaC$_6$},
author = {J. S. Kim and L. Boeri and R. K. Kremer and F. S. Razavi},
journal= {arXiv preprint arXiv:cond-mat/0603530},
year = {2015}
}