title: Infrared measurement of the pseudogap of P-doped and Co-doped high-temperature BaFe2As2 superconductors.
abstract: We report on infrared studies of charge dynamics in a prototypical pnictide system: the BaFe2As2 family. Our experiments have identified hallmarks of the pseudogap state in the BaFe2As2 system that mirror the spectroscopic manifestations of the pseudogap in the cuprates. The magnitude of the infrared pseudogap is in accord with that of the spin-density-wave gap of the parent compound. By monitoring the superconducting gap of both P- and Co-doped compounds, we find that the infrared pseudogap is unrelated to superconductivity. The appearance of the pseudogap is found to correlate with the evolution of the antiferromagnetic fluctuations associated with the spin-density-wave instability. The strong-coupling analysis of infrared data further reveals the interdependence between the magnetism and the pseudogap in the iron pnictides.
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Moon
authors.forename: A A
authors.initials: AA
authors.lastname: Schafgans
authors.forename: S
authors.initials: S
authors.lastname: Kasahara
authors.forename: T
authors.initials: T
authors.lastname: Shibauchi
authors.forename: T
authors.initials: T
authors.lastname: Terashima
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuda
authors.forename: M A
authors.initials: MA
authors.lastname: Tanatar
authors.forename: R
authors.initials: R
authors.lastname: Prozorov
authors.forename: A
authors.initials: A
authors.lastname: Thaler
authors.forename: P C
authors.initials: PC
authors.lastname: Canfield
authors.forename: A S
authors.initials: AS
authors.lastname: Sefat
authors.forename: D
authors.initials: D
authors.lastname: Mandrus
authors.forename: D N
authors.initials: DN
authors.lastname: Basov