Thermal conductivity of quasi-one-dimensional antiferromagneticspin-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: $\kappa_s\propto T^2$ at low, $\kappa_s\propto T^{-1}$ at intermediate, and $\kappa_s=const$ at higher temperatures. Our results agree very well with the existing experimental data for Sr$_2$CuO$_3$. We predict an unusual dependence on the impurity concentration for a number of observables and propose further experiments.