Abstract:

While molecular solids formed of C60 are insulators they can become superconducting under doping. An interesting purely electronic mechanism for this superconducting phase based on a favorable pair-binding energy was proposed by Kivelson, Chakravarty and Gelfand. The favorable pair-binding arises from correlation effects where the many-body states correlate in a manner so that it is energetically favorable to have 2 of the doped electrons reside on the same molecule as opposed to on different molecules. In this talk I will discuss the evidence for such an electronic mechanism in C60 as well as in C20 along with other effects such as metal insulator transitions that should occur in C20 and C36.