Evidence for a large magnetic heat current in insulating cuprates

Abstract

The in-plane thermal conductivity $k$ of the two-dimensional antiferromagnetic monolayer cuprate Sr${}_2$CuO${}_2$Cl${}_2$ is studied. Analysis of the unusual temperature dependence of $k$ reveals that at low temperatures the heat is carried by phonons, whereas at high temperatures magnetic excitations contribute significantly. Comparison with other insulating layered cuprates suggests that a large magnetic contribution to the thermal conductivity is an intrinsic property of these materials.

4 pages, 2 figures included, submitted to Phys. Rev. B