Superconducting Order Parameter Structure in the Nematic Phase of Iron-based Materials

Korshunov, M.M., Togushova, Y.N.// JETP Letters//

We consider the effect of the nematic order on the formation of the superconducting state in iron pnictides and chalcogenides. Nematic order with the B2g symmetry is modelled as the d-type Pomeranchuk instability and treated within the mean-field approach. Calculated nematic order parameter depends on the nematic interaction coefficient and abruptly changes with the coefficient’s increase. The superconducting solution is obtained within the spin-fluctuation pairing theory. We show that the leading solution in the nematic phase has a sπ± structure. From the critical temperature Tc estimations, we conclude that the nematic superconducting state of the sπ± type is more favorable than the usual s± and ��2−�2 type states appearing in the absence of the nematicity