In situ electrical resistance and activation energy of solid C₆₀ under high pressure

The in situ electrical resistance and transport activation energies of solid C₆₀ fullerene have been measured under high pressure up to 25 GPa in the temperature range of 300-423 K by using a designed diamond anvil cell. In the experiment, four parts of boron-doped diamond films fabricated on one anvil were used as electrical measurement probes and a W-Ta thin film thermocouple which was integrated on the other diamond anvil was used to measure the temperature. The current results indicate that the measured high-pressure resistances are bigger than those reported before at the same pressure and there is no pressure-independent resistance increase before 8 GPa. From the temperature dependence of the resistivity, the C₆₀ behaviors as a semiconductor and the activation energies of the cubic C₆₀ fullerene are 0.49, 0.43, and 0.36 eV at 13, 15, and 19 GPa, respectively.