The coherent potential approximation (CPA) is a method, in theoretical physics, of finding the averaged Green's function of an inhomogeneous (or disordered) system.
[1] It is perhaps most famous for its use in describing the physical properties of alloys and disordered magnetic systems,[2][3] although it is also a useful concept in understanding how sound waves scatter in a material which displays spatial inhomogeneity.
The coherent potential approximation was first described by Paul Soven,[4] and its application in the context of calculations of the electronic structure of materials was pioneered by Balász Győrffy.
The KKR-CPA has been used with success to study the physics of a variety of alloy systems,[10][11][12][13] including those where disorder is only present on one sub-lattice[14][15] (the 'inhomogeneous' CPA).
In addition, it has been shown that the CPA can very effectively describe magnetism at finite temperature, by considering (weighted) averages taken over all possible spin orientations.