Anisotropic thermal conductivity of spin ladder cuprate Sr12Ca2Cu24O41

The thermal conductivity of a single crystal of the spin ladder cuprate Sr1 2Ca2Cu24O41 has been measured in the temperature region between 5 and 300 K . An anomalous double-peak structure of the temperature dependence of the t hermal conductivity parallel to the c-axis, i.e. along the ladder direction , is observed. The high-temperature peak is absent in the thermal conductiv ity parallel to the a-axis. We suggest that the high-temperature peak is ca used by an unconventional mechanism of one-dimensional heat transport, whic h acts at temperatures exceeding approximately 40 K. (C) 2000 Elsevier Scie nce B.V. All rights reserved.