Electronic Structures and Conductivities of Fullerene C_(60) and Metal-containing Fullerenes MC_(60) (M=Li, Na, K, Rb, Cs)

Abstract

It has been reported recently that the solids K_xC_(60) and Rb_xC_(60) (x=1→5) are conductors. If x=0 and 6, they are insulators, and if x=3, they have the largest conductivities. When the temperatures go down to 18K for solid K_xC_(60) and 28K for solid Rb_xC_(60), they are transferred into superconductors. These results are very interesting. Solids K_xC_(60) and Rb_xC_(60) are very unstable when being exposed to air, so for practical purposes, it had better be synthesized to the metal-containing fullerenes MC_(60) in which the metal atom M is at the center of C_(60). It has been known for some years that