Quasiparticle interferences in the coexistence phase of iron pnictides based on a five-orbital model

We investigate quasiparticle interference in the coexistence phase of spin-density wave state and s-wave superconductivity using a five-orbital tight-binding model. We examine underdoped and overdoped cases, one with magnetic-exchange gap significantly larger than the superconducting gap, and other with both gaps being comparable. In the former case, QPI peaks are very weak or absent near (0,±π) for either of the states with s+−- or s++-wave symmetry while they are present near (±π,0) in each case, thus making any differentiation between them difficult. In the latter case, a clear distinction between the two types of states is obtained as the peaks are intense near (0,±π) and (±π,0) for the s+−- and s++-wave symmetry, respectively.