Pairon Green’s function for high-Tc superconductors

Abstract

Considering the many-body quantum dynamics, the pairon Green’s function has been developed via a Hamiltonian that encompasses the contribution of pairons, pairon-phonon interactions, anharmonicities, and defects. To obtain the renormalized pairon energy dispersion, the most relevant Born–Mayer–Huggins potential has been taken into account. The Fermi surface for the representative [Formula: see text] high-[Formula: see text] superconductor has been obtained via renormalized pairon energy relation. This revealed the [Formula: see text]-shape superconducting gap with a nodal point along [Formula: see text] direction. Further, the superconducting gap equation has been derived using the pairon density of states. The developed gap equation is the function of temperature, Fermi energy, and renormalized pairon energy. The temperature variation of the gap equation is found to be in good agreement with the BCS gap equation. Also, this reveals the reduced gap ratio ([Formula: see text] for [Formula: see text]) in the limit (5–8) of the reduced gap ratio designated for high-[Formula: see text] superconductors.