Condensed Matter Physics, 2006, vol. 9, No. 3(47), p. 619633, English
DOI:10.5488/CMP.9.3.619
Title:
Thermodynamic Green functions in theory of
superconductivity
Author(s):
 N.M.Plakida
(Joint Institute for Nuclear Research, 141980 Dubna, Russia)

A general theory of superconductivity is formulated within the thermodynamic
Green function method for various types of pairing mediated by phonons, spin
fluctuations, and strong Coulomb correlations in the Hubbard and tJ
models. A rigorous Dyson equation for matrix Green functions is derived in
terms of a selfenergy as a manyparticle Green function. By applying the
noncrossing approximation for the selfenergy, a closed selfconsistent system
of equations is obtained, similar to the conventional Eliashberg equations. A
brief discussion of superconductivity mediated by kinematic interaction with
an estimation of a superconducting transition temperature in the Hubbard model
is given.
Key words:
sGreen functions, theory of
superconductivity, strong electron correlations
PACS:
74.20.z, 74.20.Mn, 74.72.h
