title: Nonvanishing energy scales at the quantum critical point of CeCoIn5.
abstract: Heat and charge transport were used to probe the magnetic field-tuned quantum critical point in the heavy-fermion metal CeCoIn5. A comparison of electrical and thermal resistivities reveals three characteristic energy scales. A Fermi-liquid regime is observed below T(FL), with both transport coefficients diverging in parallel and T(FL) -->0 as H --> Hc, the critical field. The characteristic temperature of antiferromagnetic spin fluctuations, T(SF), is tuned to a minimum but finite value at Hc, which coincides with the end of the T-linear regime in the electrical resistivity. A third temperature scale, T(QP), signals the formation of quasiparticles, as fermions of charge e obeying the Wiedemann-Franz law. Unlike T(FL), it remains finite at Hc, so that the integrity of quasiparticles is preserved, even though the standard signature of Fermi-liquid theory fails.
authors.affiliation: Department of Physics, University of Toronto, Toronto M5S 1A7, Canada.
authors.forename: Johnpierre
authors.initials: J
authors.lastname: Paglione
authors.forename: M A
authors.initials: MA
authors.lastname: Tanatar
authors.forename: D G
authors.initials: DG
authors.lastname: Hawthorn
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: Louis
authors.initials: L
authors.lastname: Taillefer
authors.forename: C
authors.initials: C
authors.lastname: Petrovic