Quasiparticle interference in optimally doped BiS2-layered superconductors

Abstract

We theoretically investigate the quasiparticle interference (QPI) in the optimally electron-doped BiS2-layered superconductors with a two-orbital model. We show that possible pairing symmetries can be identified from their unique features in the density of states and QPI maps from magnetic or nonmagnetic impurities. Additionally, the inter-orbital nonmagnetic impurity scattering breaks the C4 symmetry and exhibits a clear C2 patterns in the QPI maps, in contrast to its negligible effect in the superconducting state of iron pnictides. The unambiguous features indicated in the QPI patterns can be used to probe the pairing symmetry as well as to uncover the impurity nature in BiS2-layered superconductors with the STM measurement.