Impact of the spin-density-wave order on the superconducting gap of Ba(Fe1-xCox)2As2

We report a doping-dependent electronic Raman-scattering measurements on iron-pnictide superconductor Ba(Fe1-xCox)(2)As-2 single crystals. The B-2g Raman spectrum at optimal doping is consistent with a strongly anisotropic gap on the electron pocket. Upon entering the coexistence region between superconducting (SC) and spin-density-wave (SDW) orders, the effective pairing energy scale is strongly reduced. Our results are interpreted in terms of a competition between SC and SDW orders for electronic states at the Fermi level. Our findings advocate for a strong connection between the SC and SDW gaps anisotropies which are both linked to interband interactions.