Superconductivity in binary alloys

The diagram variant of the coherent potential approximation for disordered alloys $B_{1-x}A_x$ in the superconducting state is developed and the self-consistent superconductive system of equations for the order parameter is derived which is valid for any impurity concentration ($0<x<1$) and for all the temperature region ($0<T<T_c$). The diagram metal–insulator for the system in the normal state is plotted. The dependence $T_c$ versus impurity concentration is investigated and it is shown that this dependence is essentially determined by the quantity $V_0=\varepsilon_A-\varepsilon_B$ where $\varepsilon_{A,B}$ are the energies of conducting electrons $A$ and $B$.