title: Scanning tunneling spectroscopy of superconducting LiFeAs single crystals: evidence for two nodeless energy gaps and coupling to a bosonic mode.
abstract: The superconducting compound LiFeAs is studied by scanning tunneling microscopy and spectroscopy. A gap map of the unreconstructed surface indicates a high degree of homogeneity in this system. Spectra at 2 K show two nodeless superconducting gaps with Δ(1)=5.3±0.1 meV and Δ(2)=2.5±0.2 meV. The gaps close as the temperature is increased to the bulk T(c), indicating that the surface accurately represents the bulk. A dip-hump structure is observed below T(c) with an energy scale consistent with a magnetic resonance recently reported by inelastic neutron scattering.
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Shun
authors.initials: S
authors.lastname: Chi
authors.forename: S
authors.initials: S
authors.lastname: Grothe
authors.forename: Ruixing
authors.initials: R
authors.lastname: Liang
authors.forename: P
authors.initials: P
authors.lastname: Dosanjh
authors.forename: W N
authors.initials: WN
authors.lastname: Hardy
authors.forename: S A
authors.initials: SA
authors.lastname: Burke
authors.forename: D A
authors.initials: DA
authors.lastname: Bonn
authors.forename: Y
authors.initials: Y
authors.lastname: Pennec