An enhancement of the in-plane thermal conductivity in the superconducting state is observed in most high-T-c superconductors. Here the observation of a similar enhancement of the thermal conductivity in copper-oxide compounds, which is not related to the superconducting transition, is reported. Since this anomaly is also accompanied by a significant variation of the electrical conductivity it indicates that a strong electron-phonon coupling exists and that thermal-conductivity enhancements in copper-oxide compounds should be attributed to an increase of its lattice component.
Cassart, M., Issi, JP., Hejtmanek, J., BrissonRobin, C., Bensalem, E., Chevalier, B., & Tressaud, A. (1996). Thermal-conductivity enhancement in copper oxide compounds. Physica C: Superconductivity and its Applications, 259(3-4), 385-391. https://doi.org/10.1016/0921-4534(96)00093-7 (Original work published 1996)