Phenomenological model of high-Tc cuprate superconductors including interlayer interactions

A phenomenological model including interlayer pairing interactions is proposed for high-Tc cuprate superconductors. Modified Eliashberg equations corresponding to the model are derived and numerically solved. The results show that the trends of Tcs for known high-Tc materials can be described reasonably well by mechanisms including (in addition to the phonon interactions) nonphonon, intralayer- and interlayer-pairing interactions. The calculated gap values (3.620/kBTc4.2) do not deviate significantly from the canonical BCS value of 3.5. This model can be applicable to layer-structured superconductors in general, whether they are high-Tc or low-Tc superconductors.