We report the in-plane and out-of-plane heat conductivity of the antiferromagnetic spin-orbit induced Mott insulator Sr2IrO4 with Jeff=1/2. Our data reveal clear-cut evidence for magnetic heat transport within the IrO2 planes which provides the unique possibility to analyze the thermal occupation and scattering of Jeff=1/2 pseudospin excitations. The analysis of the magnetic heat conductivity yields a low-temperature (T≲75 K) magnetic mean free path lmag∼32 nm, consistent with boundary scattering. Upon heating towards room temperature, the mean free path strongly decreases by one order of magnitude due to thermally activated scattering of the pseudospin excitations. The latter reveals that the coupling of these excitations to the lattice is radically different from that of S=1/2-excitations in cuprate analogs.
@article{arxiv.1507.04252,
title = {Pseudospin heat conductivity in the $J_\mathrm{eff} = 1/2$ antiferromagnet Sr$_2$IrO$_4$},
author = {Frank Steckel and Akiyo Matsumoto and Tomohiro Takayama and Hidenori Tagaki and Bernd Büchner and Christian Hess},
journal= {arXiv preprint arXiv:1507.04252},
year = {2016}
}