Generalized inclusion of short range ordering effects in the coherent potential approximation

TL;DR

This paper extends the coherent potential approximation to include short-range ordering effects in complex materials, improving the modeling of disorder in realistic solid-state systems.

Contribution

It generalizes recent theoretical methods to handle complex lattices and multiple disorder types within the CPA framework.

Findings

Successful extension to complex lattices and multiple disorder types

Application to Hapkeite compound demonstrating local environment effects

Enhanced modeling of short-range ordering in disordered materials

Abstract

The coherent potential approximation has historically allowed the efficient study of disorder effects over a variety of solid state systems. Its original formulation is however limited to a single-site or uncorrelated model of local substitutions. This neglects the effects of correlation and short range ordering, often found in realistic materials. Recent theoretical work has shown how to systematically address such shortcomings, for simple materials with only one element per unit cell. We briefly review the basic ideas of these developments within the framework of multiple scattering theory, and suggest their generalization to materials with complex lattices and possibly different types of disorder. We illustrate this extension with an example of local environment effects in the exotic Hapkeite $Fe-Fe_{37.5%}Si_{62.5%}$ compound.