Random phase approximation for multi-band Hubbard models
Strongly Correlated Electrons
2009-11-07 v1
Abstract
We derive the random-phase approximation for spin excitations in general multi-band Hubbard models, starting from a collinear ferromagnetic Hartree-Fock ground state. The results are compared with those of a recently introduced variational many-body approach to spin-waves in itinerant ferromagnets. As we exemplify for Hubbard models with one and two bands, the two approaches lead to qualitatively different results. The discrepancies can be traced back to the fact that the Hartree-Fock theory fails to describe properly the local moments which naturally arise in a correlated-electron theory.
Cite
@article{arxiv.cond-mat/0107050,
title = {Random phase approximation for multi-band Hubbard models},
author = {J. Buenemann and F. Gebhard},
journal= {arXiv preprint arXiv:cond-mat/0107050},
year = {2009}
}
Comments
25 pages, 2 figures