title: Scanning tunneling spectroscopy on the novel superconductor CaC6.
abstract: We present scanning tunneling microscopy and spectroscopy of the newly discovered superconductor CaC6. The tunneling conductance spectra, measured between 3 and 15 K, show a clear superconducting gap in the quasiparticle density of states. The gap function extracted from the spectra is in good agreement with the conventional BCS theory with Delta0=1.6+/-0.2 meV. The possibility of gap anisotropy and two-gap superconductivity is also discussed. In a magnetic field, direct imaging of the vortices allows us to deduce a coherence length in the ab plane xiab approximately 33 nm.
authors.affiliation: Institut des Nanosciences de Paris, Universités Paris 6 et 7, UMR 7588 au CNRS, 140 rue de Lourmel, 75015 Paris, France.
authors.forename: N
authors.initials: N
authors.lastname: Bergeal
authors.forename: V
authors.initials: V
authors.lastname: Dubost
authors.forename: Y
authors.initials: Y
authors.lastname: Noat
authors.forename: W
authors.initials: W
authors.lastname: Sacks
authors.forename: D
authors.initials: D
authors.lastname: Roditchev
authors.forename: N
authors.initials: N
authors.lastname: Emery
authors.forename: C
authors.initials: C
authors.lastname: Hérold
authors.forename: J-F
authors.initials: JF
authors.lastname: Marêché
authors.forename: P
authors.initials: P
authors.lastname: Lagrange
authors.forename: G
authors.initials: G
authors.lastname: Loupias