Study of the effect of spin fluctuation on the superconducting gap in the under-doped region of cuprates

Abstract

We report here a theoretical model study of the mutual influence of the spin fluctuations and the superconducting gap in the under-doped region of high-Tc cuprate systems. The system is described by the Kondo exchange model for spin interaction between the conduction and the localised impurity f-electrons besides the Heisenberg interaction among the localised f-electrons. This model is treated within a mean-field approximation and the spin components are expressed in terms of the dynamic electron operators. Further, the superconductivity (SC) in the system is described by BCS type pairing mechanism in the conduction electron. The superconducting gap as well as the spin fluctuation parameters of the conduction and localised electrons are calculated by using Zubarev's Green's function technique and are solved self-consistently. Further the tunneling conductance is reflected in the calculated electron density of states which exhibit two gap structure with prominent gap edges.