Synthesis and Electronic Transport of Single Crystal K 3 C 60

Abstract
Sizable single crystals of C6O have been synthesized and doped with potassium. Above the superconducting transition temperature Tc, the electrical resistivity p(T) displays a classic metal-like temperature dependence. The transition to the superconducting state at Tc = 19.8 K is extremely sharp, with a transition width ΔT < 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.