Electronic Pairing Interactions

The heavy fermion, actinide, cuprate, iron-pnictide/chalcogenide and Bechgaard organic salts form a class of superconducting materials which are believed to share an electronic pairing mechanism. While the early electronic pairing interactions which were suggested involved charge fluctuations, it appears that for these materials it is the spin (and orbital) fluctuations that play a central role. Here I will discuss some of what is known about the electronic pairing interaction in this class of materials and conclude with some questions for future research.