A superconducting field-effect switch (Retracted Article. See vol 298, pg 961, 2002)

We report here on a novel realization of a field-effect device that allows switching between insulating and superconducting states, which is the widest possible variation of electrical properties of a material. We chose C(60) as the active material because of its Low surface state density and observed superconductivity in alkali metal-doped C(60). We induced three electrons per C(60) molecule in the topmost molecular Layer of a crystal with the field-effect device, creating a superconducting switch operating up to 11 kelvin. An insulator was thereby transformed into a superconductor. This technique offers new opportunities for the study of superconductivity as a function of carrier concentration.