Transition temperature in superconductors with interband pairing

The pairing of electrons within the total width of the electron band, rather than only in a narrow layer near the Fermi surface, has been considered taking into account the strong electron-phonon coupling. It has been found that the effect of pairing of electrons from different bands is a decisive factor for the appearance of the effect of a high $T_c$ value in some two-band materials. The existence of an additional family of two-band hightemperature materials with the superconducting transition temperature $T_c$ no less than $T_c$ in cuprates has been predicted.