Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 22: Postersitzung III: Syst. korr. Elektr.: Theorie II (1-15), Metall-Isol.- und Phasenüberg
änge (16-33), SL: Massivmat., Bandl., Pinning, Vortexdyn., Transport, Korngr. (34-43), Niedrigdim. Syst., Magnetotransport (44-63)

TT 22.13: Poster

Donnerstag, 14. März 2002, 14:00–17:30, A

Thermal conductivity of dimerized spin-1/2 systems — •Fabian Heidrich-Meisner and Wolfram Brenig — Technische Universität Braunschweig, Institut für Theoretische Physik, Mendelsohnstraße 3, 38106 Braunschweig

We discuss the magnon heat transport of dimerized spin chains and two-leg spin-ladders. Based on a mapping of the respective spin models onto systems of interacting bond-bosons we perform a perturbative analysis of the heat-current correlation function using the Mori-Zwanzig projection technique. Results for the temperature dependence of the thermal conductivity and the current scattering rate will be presented. In addition we assess the applicability of our theory to explain recent experiments [1] which have established a surprisingly large magnetic heat conductivity in the spin-ladder compound (Sr,Ca,La)₁₄Cu₂₄O₄₁.

[1] C. Hess et al., Phys. Rev. B 64, 184305 (2001)