title: Optical study of LaO0.9F0.1FeAs: evidence for a weakly coupled superconducting state.
abstract: We have studied the reflectance of the recently discovered superconductor LaO0.9F0.1FeAs in a wide energy range from the far infrared to the visible regime. We report on the observation of infrared active phonons, the plasma edge, and possible interband transitions. On the basis of this data and the reported in-plane penetration depth lambda{L}(0)=254 nm [H. Luetkens, Phys. Rev. Lett. 101, 097009 (2008)] a disorder sensitive relatively small value of the total electron-boson coupling constant lambda{tot}=lambda{e-ph}+lambda{e-sp} approximately 0.6+/-0.35 can be estimated adopting an effective single-band picture.
authors.affiliation: IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany. drechsler@ifw-dresden.de
authors.forename: S-L
authors.initials: SL
authors.lastname: Drechsler
authors.forename: M
authors.initials: M
authors.lastname: Grobosch
authors.forename: K
authors.initials: K
authors.lastname: Koepernik
authors.forename: G
authors.initials: G
authors.lastname: Behr
authors.forename: A
authors.initials: A
authors.lastname: Köhler
authors.forename: J
authors.initials: J
authors.lastname: Werner
authors.forename: A
authors.initials: A
authors.lastname: Kondrat
authors.forename: N
authors.initials: N
authors.lastname: Leps
authors.forename: C
authors.initials: C
authors.lastname: Hess
authors.forename: R
authors.initials: R
authors.lastname: Klingeler
authors.forename: R
authors.initials: R
authors.lastname: Schuster
authors.forename: B
authors.initials: B
authors.lastname: Büchner
authors.forename: M
authors.initials: M
authors.lastname: Knupfer