Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 22: SKM Symposium: Spin Caloric Transport (SYST)
HL 22.4: Hauptvortrag
Montag, 14. März 2011, 16:00–16:30, TRE Ma
Heat conduction of low-dimensional quantum magnets — •Christian Hess1, Nikolai Hlubek1, Patrick Ribeiro1, Bernd Büchner1, Surjeet Singh2, Romuald Saint-Martin2, and Alexandre Revcolevschi2 — 1Leibniz-Institute for Solid State and Materials Research, IFW Dresden, Institute for Solid State Research, 01171 Dresden, Germany — 2Laboratoire de Physico-Chimie de L’Etat Solide, ICMMO, UMR8182, Université Paris-Sud, 91405 Orsay, France
Some years ago, a new, magnetic mode of heat transport which occurs in low-dimensional S=1/2 quantum magnets has been discovered and is intensely studied since then. The magnetic heat conductivity κmag of such quantum magnet materials can be exceptionally large (even at room temperature), dwarfs the phonon heat conduction and thereby leads to an overall magnitude of the heat conductivity which is comparable to that of metals. The analysis of κmag yields detailed information about the scattering processes which govern the magnon transport, such as scattering involving defects, phonons and magnons in the materials. After reviewing the main experimental findings, this talk focuses on recent experimental results on one-dimensional S=1/2 Heisenberg chain materials. Evidence for ballistic magnetic transport and magnetic mean free paths of more than one micrometer is found in these materials, i.e. at the length scale of typical spin diffusion lengths in spintronic experiments. In our experiments we carefully study the effect of various disorder types (viz. bond disorder, magnetic and non-magnetic site disorder) on this transport phenomenon.