Evidence of one-dimensional magnetic heat transport in the triangular-lattice antiferromagnet Cs_{2}CuCl_{4}

Abstract

We report on low-temperature heat-transport properties of the spin-1/2 triangular-lattice antiferromagnet Cs_{2}CuCl_{4}. Broad maxima in the thermal conductivity along the three principal axes, observed at about 5 K, are interpreted in terms of the Debye model, including the phonon umklapp scattering. For thermal transport along the b axis, we found a pronounced field-dependent anomaly, close to the transition into the three-dimensional long-range-ordered state. No such anomalies were found for the transport along the a and c directions. We argue that this anisotropic behavior is related to an additional heat-transport channel through magnetic excitations, that can best propagate along the direction of the largest exchange interaction. In addition, peculiarities of the heat transport of Cs_{2}CuCl_{4} in magnetic fields up to the saturation field and above are discussed.