Abstract:
In the electronic theory of disordered alloys an expansion with respect
to the parameter $\gamma=\exp(-1/\xi)$, where $\xi$ is the dimensionless correlation
length of the single-electron Green's function, is proposed. This
expansion makes it possible to take into account the presence in the
alloy of short-range order and the effects of multiple scattering of the
electrons by different sites. It is shown that in the case of
sufficiently strong disorder $\gamma$ is a small parameter of the coherent
potential approximation, and the corrections to this approximation are
found. It is also shown that in the framework of this approximation
the equilibrium values of the parameters of the short-range order can be calculated.