Scanning tunneling spectroscopy on the novel superconductor CaC6.
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.
Bergeal
N
N
Institut des Nanosciences de Paris, Universités Paris 6 et 7, UMR 7588 au CNRS, 140 rue de Lourmel, 75015 Paris, France.
Dubost
V
V
Noat
Y
Y
Sacks
W
W
Roditchev
D
D
Emery
N
N
Hérold
C
C
Marêché
J-F
JF
Lagrange
P
P
Loupias
G
G