Quasiparticle scattering interference in superconducting iron pnictides

Using both two orbital and five orbital models, we investigate the quasiparticle interference (QPI) patterns in the superconducting (SC) state of iron-based superconductors. We compare the results for nonmagnetic and magnetic impurities in sign-changed s-wave cos(k(x))center dot cos(k(y)) and sign-unchanged vertical bar cos(k(x))center dot cos(k(y))vertical bar SC states. While the patterns strongly depend on the chosen band structure details, the sensitivity of peaks around (+/-pi,0) and (0,+/-pi) wave vectors on magnetic or nonmagnetic impurities, and on sign-changed or sign-unchanged SC orders is a common feature. Our results suggest that the QPI can provide evidence of the pairing symmetry in the SC states.