Effect of interlayer Josephson coupling in the high T-c superconductors

The enhancement of the transition temperature by the Josephson coupling of the CuO2 layers high T-c superconductor is studied within the framework of the Eliashberg strong coupling formalism. It is assumed that the electron-phonon interaction is the primary mechanism for superconductivity in the high T-c superconductors. The microscopically derived expression for T-c is found to be very similar to the macroscopically (Ginzberg-Landau) based expression for T-c. The microscopic expression shows explicitly the dependence of T-c on various parameters, i.e., the quadratic dependence of T-c on the strength of the interlayer interaction. Discussion of possible implications of the expressions is given.