Anisotropic thermal conductivity of spin ladder cuprate Sr12Ca2Cu24O41

Abstract The thermal conductivity of a single crystal of the spin ladder cuprate Sr 12 Ca 2 Cu 24 O 41 has been measured in the temperature region between 5 and 300 K. An anomalous double-peak structure of the temperature dependence of the thermal conductivity parallel to the c -axis, i.e. along the ladder direction, is observed. The high-temperature peak is absent in the thermal conductivity parallel to the a -axis. We suggest that the high-temperature peak is caused by an unconventional mechanism of one-dimensional heat transport, which acts at temperatures exceeding approximately 40 K.