Recent experiments on ${\text{CeCoIn}}_5$ suggest an unusual interplay between superconducting and magnetic orders that gives rise to a multicomponent (magnetosuperconducting) phase. We demonstrate that characteristics of ${\text{CeCoIn}}_5$ make this system particularly well suited for the onset of such a phase. Based on general considerations, we show that superconductivity with nonzero Cooper-pair momentum may lead to an enhancement of the spin-spin response function and, simultaneously, incommensurate spin-density wave may enhance the Cooper-pair susceptibility.

• Received 30 July 2009

DOI:https://doi.org/10.1103/PhysRevB.80.174525