THERMAL-CONDUCTIVITY ENHANCEMENT IN COPPER-OXIDE COMPOUNDS

An enhancement of the in-plane thermal conductivity in the superconduc ting state is observed in most high-T-c superconductors. Here the obse rvation of a similar enhancement of the thermal conductivity in copper -oxide compounds, which is not related to the superconducting transiti on, is reported. Since this anomaly is also accompanied by a significa nt variation of the electrical conductivity it indicates that a strong electron-phonon coupling exists and that thermal-conductivity enhance ments in copper-oxide compounds should be attributed to an increase of its lattice component.