Abstract
Superconductivity in graphite intercalation compounds, C4nMHg (M:K, Rb, n=1,2) and C4KTl1.5 is studied in ambient as well as elevated pressures. It is argued that the major role in the superconductivity of this class of materials is played by electrons in the intercalant bands rather than those in the graphite bands. It is experimentally demonstrated that the two-dimensional anisotropy of the superconductivity is controlled by stage and pressure.