Strong-coupling effects in high-T c superconductors

It is conceivable that the high-T_c superconducting perovskites are conventional electronphonon superconductors. In this case one expects significant strong-coupling effects because of the unusually high ratiok_BT_c/ of the order 0.1 and greater. We use a set of reasonable models for the Eliashberg function ²F() (which takes into account available information on the phonon spectra and which fit the measuredT_c's) and calculate strong-coupling effects in the specific heatc_s(T)/T_c, the ratio ₀/k_BT_c, the critical fieldsH_c(T) andH_c2(T) including Pauli limiting, and other measurable quantities. Strongcoupling corrections turn out to be in the range of 0 to about 100%, depending on the quantity of interest. We discuss the perspectives of using strong-coupling effects as indicators for conventional electron-phonon superconductivity in the new materials.