High-Temperature Superconductivity in Lattice-Expanded C 60

Abstract
C 60 single crystals have been intercalated with CHCl 3 and CHBr 3 in order to expand the lattice. High densities of electrons and holes have been induced by gate doping in a field-effect transistor geometry. At low temperatures, the material turns superconducting with a maximum transition temperature of 117 K in hole-doped C 60 /CHBr 3 . The increasing spacing between the C 60 molecules follows the general trend of alkali metal–doped C 60 and suggests routes to even higher transition temperatures.