Anomalous thermal transport and strong violation of Wiedemann-Franz law in the critical regime of a charge density wave transition

This is the authors' abstract. We don't add key points for this paper.

ErTe₃ is a model system used to explore thermal transport in a layered charge density wave (CDW) material. We present thermal diffusivity, resistivity, and specific-heat data: There is a sharp decrease in thermal conductivity parallel and perpendicular to the primary CDW at the CDW transition temperature. Yet, the resistivity changes more gradually. Using the Wiedemann-Franz law well above and below Tc a consistent description of the thermal transport applies with essentially independent electron and phonon contributions. In the critical regime, no such description is possible; the observed behavior corresponds to a strongly coupled electron-phonon critical ``soup.''