Weighted two-particle Green's functions in the coherent-potential approximation
Abstract
We extend the two-particle theory of disordered systems within the coherent-potential approximation to obtain weighted contributions to averaged two-particle resolvents which arise from separate alloy components. Starting from first principles in a model of diagonal disorder and the single-site approximation for a binary substitutional alloy AcB1-c we extend the approach of a fundamental paper by Velický to evaluate various weighted forms of a general class of two-particle Green's functions. Applications in a wide range of linear response theory are discussed in detail as well as the behavior of the weighted functions in a strong disorder limit. To exemplify our analytic calculations the optical absorption in a disordered model alloy is studied numerically.
- Publication:
-
Physical Review B
- Pub Date:
- March 1996
- DOI:
- 10.1103/PhysRevB.53.5301
- Bibcode:
- 1996PhRvB..53.5301S
- Keywords:
-
- 71.10.-w;
- 71.55.-i;
- 72.10.Fk;
- 78.30.-j;
- Theories and models of many-electron systems;
- Impurity and defect levels;
- Scattering by point defects dislocations surfaces and other imperfections;
- Infrared and Raman spectra