title: Splitting of resonance excitations in nearly optimally doped Ba(Fe0.94Co0.06)2As2: an inelastic neutron scattering study with polarization analysis.
abstract: Magnetic excitations in Ba(Fe0.94Co0.06)2As2: are studied by polarized inelastic neutron scattering above and below the superconducting transition. In the superconducting state, we find clear evidence for two resonancelike excitations. At a higher energy of about 8 meV, there is an isotropic resonance mode with weak dispersion along the c direction. In addition, we find a lower excitation at 4 meV that appears only in the c-polarized channel and whose intensity strongly varies with the l component of the scattering vector. These resonance excitations behave remarkably similar to the gap modes in the antiferromagnetic phase of the parent compound BaFe2As2.
authors.affiliation: Institut Laue Langevin, 6 Rue Jules Horowitz, BP 156, F-38042 Grenoble Cedex 9, France. steffens@ill.eu
authors.forename: P
authors.initials: P
authors.lastname: Steffens
authors.forename: C H
authors.initials: CH
authors.lastname: Lee
authors.forename: N
authors.initials: N
authors.lastname: Qureshi
authors.forename: K
authors.initials: K
authors.lastname: Kihou
authors.forename: A
authors.initials: A
authors.lastname: Iyo
authors.forename: H
authors.initials: H
authors.lastname: Eisaki
authors.forename: M
authors.initials: M
authors.lastname: Braden