title: Bulk evidence for single-Gap s-wave superconductivity in the intercalated graphite superconductor C6Yb.
abstract: We report measurements of the in-plane electrical resistivity rho and thermal conductivity kappa of the intercalated graphite superconductor C6Yb down to temperatures as low as Tc/100. When a field is applied along the c axis, the residual electronic linear term kappa0/T evolves in an exponential manner for Hc1<H<Hc2/2. This activated behavior is compelling evidence for an s-wave order parameter, and is a strong argument against the possible existence of multigap superconductivity.
authors.affiliation: Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 OHE, United Kingdom.
authors.forename: Mike
authors.initials: M
authors.lastname: Sutherland
authors.forename: Nicolas
authors.initials: N
authors.lastname: Doiron-Leyraud
authors.forename: Louis
authors.initials: L
authors.lastname: Taillefer
authors.forename: Thomas
authors.initials: T
authors.lastname: Weller
authors.forename: Mark
authors.initials: M
authors.lastname: Ellerby
authors.forename: S S
authors.initials: SS
authors.lastname: Saxena