Critical Temperature Tc versus Charging Energy Ec in Molecular-Intercalated Fullerenes

Abstract

We study the recently discovered 117-Kelvin superconducting system C60/CHBr3 of the field-effect transistor and propose a possibility that the intercalation molecule CHBr3 plays a role of an electric capacitor in the C60 fullerene superconductor, which contrasts rather with an expectation that the intercalation molecule in that system acts as simple spacer molecule. Estimating the critical temperatures Tc for several C60/X (X: intercalation molecule), we suggest searching for intercalation molecules with large molecular polarizabilities, in order to attain higher Tc in the synthesis of fullerene superconductors and to more systematically develop high Tc superconducting electronic devices.