Evidence for spinon localization in the heat transport of the spin-1/2 ladder compound (C5H12N)(2)CuBr4

We present experiments on the magnetic-field-dependent thermal transport in the spin-1/2 ladder system (C5H12N)(2)CuBr4. The thermal conductivity kappa(B) is only weakly affected by the field-induced transitions between the gapless Luttinger-liquid state realized for B-c1 < B < B-c2 and the gapped states, suggesting the absence of a direct contribution of the spin excitations to the heat transport. We observe, however, that the thermal conductivity is strongly suppressed by the magnetic field deeply within the Luttinger-liquid state. These surprising observations are discussed in terms of localization of spinons within finite ladder segments and spinon-phonon umklapp scattering of the predominantly phononic heat transport.


Published in:
Phys. Rev. B, 80, 22, 220411
Year:
2009
Keywords:
Note:
LQM
Laboratories:




 Record created 2010-02-08, last modified 2018-03-17

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