Heat conductivity of the spin-Peierls compounds TiOCl and TiOBr

N. Hlubek, M. Sing, S. Glawion, R. Claessen, S. van Smaalen, P. H. M. van Loosdrecht, B. Büchner, and C. Hess
Phys. Rev. B 81, 144428 – Published 28 April 2010

Abstract

We report experimental results on the heat conductivity κ of the S=1/2 spin chain compounds TiOBr and TiOCl for temperatures 5K<T<300K and magnetic fields up to 14 T. Surprisingly, we find no evidence of a significant magnetic contribution to κ, which is in stark contrast to recent results on S=1/2 spin chain cuprates. Despite this unexpected result, the thus predominantly phononic heat conductivity of these spin-Peierls compounds exhibits a very unusual behavior. In particular, we observe strong anomalies at the phase transitions Tc1 and Tc2. Moreover, we find an overall but anisotropic suppression of κ in the intermediate phase which extends even to temperatures higher than Tc2. An external magnetic field causes a slight downshift of the transition at Tc1 and enhances the suppression of κ up to Tc2. We interpret our findings in terms of strong spin-phonon coupling and phonon scattering arising from spin-driven lattice distortions.

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  • Received 10 February 2010

DOI:https://doi.org/10.1103/PhysRevB.81.144428

©2010 American Physical Society

Authors & Affiliations

N. Hlubek1, M. Sing2, S. Glawion2, R. Claessen2, S. van Smaalen3, P. H. M. van Loosdrecht4, B. Büchner1, and C. Hess1

  • 1IFW-Dresden, Institute for Solid State Research, P.O. Box 270116, D-01171 Dresden, Germany
  • 2Experimentelle Physik 4, Universität Würzburg, 97074 Würzburg, Germany
  • 3Laboratory of Crystallography, Universität Bayreuth, 95440 Bayreuth, Germany
  • 4Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands

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Issue

Vol. 81, Iss. 14 — 1 April 2010

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