Pressure Dependence of Superconductivity in Single-Phase K 3 C 60

Abstract
The superconducting compound K 3 C 60 (with transition temperature T c = 19.3 kelvin at ambient pressure), formed as a single phase by reaction of alkali vapor with solids of the icosahedral C 60 molecule (buckminsterfullerene), shows a very large decrease of T c with increasing pressure. Susceptibility measurements on sintered pellets showing bulk superconductivity are reported up to 21 kilobars of pressure, where T c is already less than 8 kelvin. The results are consistent with a piling up of the density of states at the Fermi level.