Self-consistent cluster CPA methods and the nested CPA theory
摘要
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.
引用
@article{arxiv.cond-mat/9912305,
title = {Self-consistent cluster CPA methods and the nested CPA theory},
author = {C. I. Ventura and R. A. Barrio and .},
journal= {arXiv preprint arXiv:cond-mat/9912305},
year = {2009}
}
备注
5 pages + 2 figures, to appear in Physica B. Presented at the SCES'99 conference, Nagano, Japan (Aug.'99)