Exotic pairing instability in the heavy-fermion superconductor CeCoIn 5

Superconductivity in the heavy-fermion compound CeCoIn5 has recently been found to be due to multiple-band effects (Phys. Rev. Lett., 94 (2005) 107005) with a distinct two-gap structure. It is shown here that the enormously enhanced values of the gap ratios with respect to Tc have an unusual origin with the electron dynamics mainly governed by f-p hybridization.