title: Pairing state with a time-reversal symmetry breaking in FeAs-based superconductors.
abstract: We investigate the competition between the extended s+/--wave and dx2-y2-wave pairing order parameters in the iron-based superconductors. Because of the frustrating pairing interactions among the electron and the hole Fermi pockets, a time-reversal symmetry breaking s+id pairing state could be favored. We analyze this pairing state within the Ginzburg-Landau theory and explore the experimental consequences. In such a state, spatial inhomogeneity induces a supercurrent near a nonmagnetic impurity and the corners of a square sample. The resonance mode between the s+/-- and dx2-y2-wave order parameters can be detected through the B1g Raman spectroscopy.
authors.affiliation: Department of Physics, University of California, San Diego, California 92093, USA.
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Lee
authors.forename: Shou-Cheng
authors.initials: SC
authors.lastname: Zhang
authors.forename: Congjun
authors.initials: C
authors.lastname: Wu