title: Highly anisotropic gap function in borocarbide superconductor LuNi(2)B(2)C.
abstract: The thermal conductivity of borocarbide superconductor LuNi(2)B(2)C was measured down to 70 mK (T(c)/200) in a magnetic field perpendicular to the heat current from H = 0 to above H(c2) = 7 T. As soon as vortices enter the sample, the conduction at T-->0 grows rapidly, showing unambiguously that delocalized quasiparticles are present at the lowest energies. The field dependence is very similar to that of UPt(3), a heavy-fermion superconductor with a line of nodes in the gap, and very different from the exponential dependence characteristic of s-wave superconductors. This is strong evidence for a highly anisotropic gap function in LuNi(2)B(2)C, possibly with nodes.
authors.affiliation: Canadian Institute for Advanced Research, Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Boaknin
authors.forename: R W
authors.initials: RW
authors.lastname: Hill
authors.forename: C
authors.initials: C
authors.lastname: Proust
authors.forename: C
authors.initials: C
authors.lastname: Lupien
authors.forename: L
authors.initials: L
authors.lastname: Taillefer
authors.forename: P C
authors.initials: PC
authors.lastname: Canfield