Fermi-Liquid Behavior and BCSs-Wave Pairing of K3C60Observed by13C-NMR

Abstract
This Letter reports on NMR studies of 13 C in K 3 C 60 above and below T c with an applied field of 2.93 T. It is found that non-single-exponential recovery data can be fitted by two components and normalized to an identical shape. With T 1 defined in this way, Fermi-liquid behavior is identified above T c , and a broadened Hebel-Slichter peak observed below T c is well explained by the Eliashberg theory with 2Δ(0)/ k B T c =4.31. The possibility of strong electron correlation and the origin of the multi-exponential recovery are discussed.