Application of Plasmon Exchange Model to High-Tc Superconductivity

Abstract

A plasmon exchange model for the occurrence of superconductivity in the cuprate superconductors is presented. Analytic expressions for the effective interaction due to plasmon exchanges between the charge carriers (holes or electrons) in the CuO layers of the cuprates are first calculated for samples with one-, two-, three-, and four-CuO layers per unit cell. Then using the Eliashberg model for strong coupling superconductors, it is shown that these interactions can lead to superconductivity. The resulting theory is able to explain qualitatively the experimentally observed rise in Tc with the increase in the number of CuO layers per unit cell in the T1- and Bi-based compounds. This calculation also indicates that there is a saturation effect, i.e. Tc cannot be increased indefinitely by stacking more CuO layers per cell. Application of this model to the calculation of the infra-red absorption in the layered compounds shows a linear ω dependence of the loss function.