Thermal Conductivity of Quasi-One-Dimensional Antiferromagnetic Spin-Chain Materials

We study heat transport in quasi-one-dimensional spin-chain systems by considering the model of one-dimensional bosonic spin excitations interacting with three-dimensional phonons and impurities in the limit of weak spin-lattice coupling and fast spin excitations. A combined effect of the phonon and impurity scatterings yields the following spin-boson thermal conductivity behavior: κ_s∝T² at low, κ_s∝T^-1 at intermediate, and κ_s= const at higher temperatures. Our results agree well with the existing experimental data for Sr₂CuO₃. We predict an unusual dependence on the impurity concentration for a number of observables and propose further experiments.