title: Linear temperature dependence of the magnetic heat conductivity in CaCu2O3.
abstract: We present experimental results for the thermal conductivity kappa of the pseudo-two-leg ladder material CaCu2O3. The strong buckling of the ladder rungs renders this material a good approximation to a S=1/2 Heisenberg chain. Despite a strong suppression of the thermal conductivity of this material in all crystal directions due to inherent disorder, we find a dominant magnetic contribution kappa mag along the chain direction. kappa mag is linear in temperature, resembling the low-temperature limit of the thermal Drude weight D th of the S=1/2 Heisenberg chain. The comparison of kappamag and Dth yields a magnetic mean-free path of l mag approximately 22+/-5 A, in good agreement with magnetic measurements.
authors.affiliation: Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, 01171 Dresden, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Hess
authors.forename: H
authors.initials: H
authors.lastname: Elhaes
authors.forename: A
authors.initials: A
authors.lastname: Waske
authors.forename: B
authors.initials: B
authors.lastname: Büchner
authors.forename: C
authors.initials: C
authors.lastname: Sekar
authors.forename: G
authors.initials: G
authors.lastname: Krabbes
authors.forename: F
authors.initials: F
authors.lastname: Heidrich-Meisner
authors.forename: W
authors.initials: W
authors.lastname: Brenig