Metallic Behavior In The Potassium-Doped Fullerene-Cubane Copolymer

C-60 and C-70 form with cubane (C8H8) molecules rotor-stator phases in which the fullerenes are rotating and the cubanes are static. Heating the rotor-stator phase up to 470 K a fulleride copolymer, poly (C60C8H8), is obtained. Here, we study using microwave conductivity measurements, electron-spin resonance, and superconducting quantum interference device magnetometry the effect of potassium intercalation on the electric and magnetic properties of poly (C60C8H8). The resulting K2C60C8H8 copolymer is metallic for T > 200 K in contrast to the insulating pristine poly (C60C8H8) copolymer. At lower temperatures, a disorder-driven Anderson localization of the electrons takes place and the ground state is a magnetic insulator.