title: Magnetothermal transport in the spin-1/2 chains of copper pyrazine dinitrate.
abstract: We present experiments on the thermal transport in the spin-1/2 chain compound copper pyrazine dinitrate Cu(C4H4N2)(NO3)2. The heat conductivity shows a surprisingly strong dependence on the applied magnetic field B, characterized at low temperatures by two main features. The first one appearing at low B is a characteristic dip located at muBB approximately kBT, that may arise from umklapp scattering. The second one is a plateaulike feature in the quantum critical regime, muB|B - Bc| < kBT, where Bc is the saturation field at T=0. The latter feature clearly points towards a momentum and field-independent mean free path of the spin excitations, contrary to theoretical expectations.
authors.affiliation: II. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany.
authors.forename: A V
authors.initials: AV
authors.lastname: Sologubenko
authors.forename: K
authors.initials: K
authors.lastname: Berggold
authors.forename: T
authors.initials: T
authors.lastname: Lorenz
authors.forename: A
authors.initials: A
authors.lastname: Rosch
authors.forename: E
authors.initials: E
authors.lastname: Shimshoni
authors.forename: M D
authors.initials: MD
authors.lastname: Phillips
authors.forename: M M
authors.initials: MM
authors.lastname: Turnbull