title: Theoretical approach to resonant inelastic x-ray scattering in iron-based superconductors at the energy scale of the superconducting gap.
abstract: We develop a phenomenological theory to predict the characteristic features of the momentum-dependent scattering amplitude in resonant inelastic x-ray scattering (RIXS) at the energy scale of the superconducting gap in iron-based super-conductors. Taking into account all relevant orbital states as well as their specific content along the Fermi surface we evaluate the charge and spin dynamical structure factors for the compounds LaOFeAs and LiFeAs, based on tight-binding models which are fully consistent with recent angle-resolved photoemission spectroscopy (ARPES) data. We find a characteristic intensity redistribution between charge and spin dynamical structure factors which discriminates between sign-reversing and sign-preserving quasiparticle excitations. Consequently, our results show that RIXS spectra can distinguish between s± and s++ wave gap functions in the singlet pairing case. In addition, we find that an analogous intensity redistribution at small momenta can reveal the presence of a chiral p-wave triplet pairing.
authors.affiliation: CNR-SPIN Salerno, I-84084 Fisciano (Salerno), Italy.|Department of Physics "E. R. Caianiello", University of Salerno, I-84084 Fisciano (Salerno), Italy.|Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Marra
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany.|Department of Physics, TU Dresden, D-01062 Dresden, Germany.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Brink
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Sykora