Self-consistent cluster CPA methods and the nested CPA theory

C. I. Ventura; R. A. Barrio; .

doi:10.1016/s0921-4526(99)01160-6

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arXiv · cond-mat/9912305

Self-consistent cluster CPA methods and the nested CPA theory

C. I. Ventura·R. A. Barrio·.

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Abstract

The coherent potential approximation, CPA, is a useful tool to treat systems with disorder. Cluster theories have been proposed to go beyond the translation invariant single-site CPA approximation and include some short range correlations. In this framework one can also treat simultaneously diagonal disorder (in the site-diagonal elements of the Hamiltonian) and non-diagonal disorder (in the bond energies). It proves difficult to obtain reasonable results, free of non-analyticities, for lattices of dimension higher than one (D>1). We show electronic structure results obtained for a Hubbard model, treated in mean field approximation, on a square lattice and a simple cubic lattice, with the simultaneous inclusion of diagonal and non-diagonal disorder. We compare the results obtained using three different methods to treat the problem: a self-consistent 2-site cluster CPA method, the Blackman-Esterling-Berk single-site like extension of the CPA and a nested CPA approach.

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C. I. Ventura, R. A. Barrio, .. 1999-12-16. Self-consistent cluster CPA methods and the nested CPA theory. https://doi.org/10.1016/s0921-4526(99)01160-6

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