The role of anomalous strength operator in the high- [formula omitted] superconductivity theory

Abstract

The diagram series structure for Matsubara Green's functions in the Hubbard operators representation have been analyzed for the superconducting (SC) phase in the t – J -model. It has been found that the Hubbard operator diagram technique besides anomalous self-energy operator includes also anomalous strength operator (ASO). With account for ASO Gor’kov equations have been written. ASO are shown to be very essential when anomalous averages are calculated. The anomalous self-energy operator and ASO were derived in one-loop approximation. It has turned out that strength operator components depend on Matsubara frequency. As a result the SC phase is described by infinite set of integral equations. When deriving the equation for transition temperature in SC phase with s- and d-order parameter symmetry this system has been solved exactly. On the basis of numerical calculations it has been found that the account for strength operator components has fully suppressed SC phase with s-order parameter symmetry in the t – J -model.