Robust s±s±-wave superconductivity against multi-impurity in iron-based superconductors

• Multiple impurities with same scattering potential (SP) are randomly distributed.
• Probability distribution of order parameters is investigated for different cases.
• s±s±-wave superconductivity is robust against multi-impurity, while magnetism is more sensitive to it.
• TC does not have qualitative change for small impurity concentration.

Effects of disorder on electron-doped iron pnictides are investigated systematically based on self-consistent Bogoliubov-de Gennes equations. Multiply impurities with same scattering potential (SP) are randomly distributed in a square lattice. Probability distribution functions of normalized order parameters for different impurity concentrations δimpδimp, different electron doping concentrations δδ are investigated for given SPs. Samples are found to be very robust against weak SP, in which order parameters do not have qualitative change even at very large δimpδimp. While strong SP is able to easily break down the order parameters. For moderate SP, variations of order parameters on and around impurities strongly depend on δδ, however the distribution functions of normalized order parameters have similar behavior as δimpδimp increases. Compared with superconducting (SC) order, the magnetic order is more sensitive to multi-impurity effect. The spatial spin density wave pattern has already been destroyed before the system loses its superconductivity. Dependence of SC order on temperature is similar to that of impurity-free case, with the critical temperature being remarkably suppressed for high δimpδimp.