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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.10: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Heat transport in one-dimensional quantum magnets — •C. Hess¹, P. Ribeiro¹, A. Waske¹, N. Wizent¹, R. Klingeler¹, D. Elefant¹, C. Sekar¹, G. Krabbes¹, B. Büchner¹, H. ElHaes², G. Roth², F. Heidrich-Meisner³, and W. Brenig³ — ¹IFW Dresden, Germany — ²RWTH Aachen, Germany — ³Institut für Theoretische Physik, TU-Braunschweig, Germany

We present experimental results for the magnon thermal conductivity κ_mag of several one-dimensional S=1/2 spin systems, like spin ladders and chains. We put a focus on spin chain materials such as SrCuO₂ and CaCu₂O₃. SrCuO₂ exhibits a strong signature of κ_mag from spinons. However, the size of κ_mag is difficult to determine due to its coincidence with the peak of the phonon thermal conductivity κ_ph. In order to obtain a better separation of κ_mag and κ_ph we selectively suppress κ_ph by substituting Ca for Sr. A strong signature of magnetic heat transport is also present in CaCu₂O₃ along its chains. Since κ_ph is strongly suppressed in this material the temperature dependence of κ_mag can be well extracted. We estimate the magnetic mean free path which turns out to be of the order of 25 Å.