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. Buechner, C. Hess, B. Büchner

*Corresponding author for this work

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Abstract

We report experimental results on the heat conductivity kappa of the S=1/2 spin chain compounds TiOBr and TiOCl for temperatures 5 K <T <300 K and magnetic fields up to 14 T. Surprisingly, we find no evidence of a significant magnetic contribution to kappa, 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 T(c1) and T(c2). Moreover, we find an overall but anisotropic suppression of kappa in the intermediate phase which extends even to temperatures higher than T(c2). An external magnetic field causes a slight downshift of the transition at T(c1) and enhances the suppression of kappa up to T(c2). We interpret our findings in terms of strong spin-phonon coupling and phonon scattering arising from spin-driven lattice distortions.

Original languageEnglish
Article number144428
Pages (from-to)144428-1-144428-5
Number of pages5
JournalPhysical Review. B: Condensed Matter and Materials Physics
Volume81
Issue number14
DOIs
Publication statusPublished - 1-Apr-2010

Keywords

  • THERMAL-CONDUCTIVITY
  • SYSTEM TIOBR
  • TRANSPORT
  • CUGEO3
  • TRANSITION
  • SCATTERING
  • EXAMPLE
  • CHAIN

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