Critical magnetic-fluctuations-induced superconductivity and residual density of states in the CeRhIn5 superconductor -: art. no. 224501

We propose a multiband extension of the spin-fermion model to address the superconducting d-wave pairing due to magnetic interaction near the critical point. We solve the unrestricted gap equation with a general d-wave symmetry gap, and find that the divergent magnetic correlation length xi leads to the very unharmonic shape of the gap function with shallow gap regions near the nodes. These regions are extremely sensitive to disorder. A small impurity concentration induces a substantial residual density of states. We argue that we can understand the large N-res(0)=lim(T-->0)C(p)(T)/T value and its pressure dependence of the recently discovered CeRhIn5 superconductor under pressure within this approach.