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

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 T-c 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.

Automated summary

ErTe3 serves as a model system to study thermal transport in layered charge density wave materials. Thermal diffusivity, resistivity, and specific-heat data show a sharp decrease in thermal conductivity at the CDW transition temperature, while resistivity changes more gradually. In the critical regime, the behavior corresponds to a strongly coupled electron-phonon critical soup where traditional description is not possible.