Thermodynamics of Superconductors with Charge‐ and Spin‐Density Waves

Using thermal Green's function technique the thermodynamics of superconductors with charge‐ and spin‐density waves is considered. The Δ/ T c ratio and the paramagnetic limit H p are calculated for various values of the dielectric gap σ and the parameter ν = N nd (0)/ N d (0), where N nd (0) and N d (0) are the electron densities of states for non‐dielectrized and dielectrized Fermi surface sections, Δ(0) is the zero‐temperature value of the superconducting order parameters, and T c is the critical temperature. It is shown that for the charge‐density wave‐superconductors the values Δ(0)/ T c are substantially less than in the conventional BCS theory. The theoretical conclusions are in a good agreement with the experiment.