title: Thermal conductivity in the vicinity of the quantum critical end point in Sr3Ru2O7.
abstract: Thermal conductivity of Sr3Ru2O7 was measured down to 40 mK and at magnetic fields through the quantum critical end point at Hc=7.85 T. A peak in the electrical resistivity as a function of the field was mimicked by the thermal resistivity. In the limit as T-->0 K, we find that the Wiedemann-Franz law is satisfied to within 5% at all fields, implying that there is no breakdown of the electron despite the destruction of the Fermi liquid state at quantum criticality. A significant change in disorder [from rho0(H=0 T)=2.1 to 0.5 microOmega cm] does not influence our conclusions. At finite temperatures, the temperature dependence of the Lorenz number is consistent with ferromagnetic fluctuations causing the non-Fermi liquid behavior as one would expect at a metamagnetic quantum critical end point.
authors.affiliation: Department of Physics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Ronning
authors.forename: R W
authors.initials: RW
authors.lastname: Hill
authors.forename: M
authors.initials: M
authors.lastname: Sutherland
authors.forename: D G
authors.initials: DG
authors.lastname: Hawthorn
authors.forename: M A
authors.initials: MA
authors.lastname: Tanatar
authors.forename: J
authors.initials: J
authors.lastname: Paglione
authors.forename: Louis
authors.initials: L
authors.lastname: Taillefer
authors.forename: M J
authors.initials: MJ
authors.lastname: Graf
authors.forename: R S
authors.initials: RS
authors.lastname: Perry
authors.forename: Y
authors.initials: Y
authors.lastname: Maeno
authors.forename: A P
authors.initials: AP
authors.lastname: Mackenzie