Synthesis and electronic transport of single crystal K3C60

Sizable single crystals of C60 are synthesized and doped with potassium. Above the superconducting transition temperature Tc, the electrical resistivity displays a classic metallike temperature dependence. The transition to the superconducting state at Tc = 19.8 K is extremely sharp, with a transition width of less than 200 mK. In contrast to transport behavior of doped polycrystalline and granular thin films no anomalous fluctuations are observed near Tc in single crystal specimens.