Eur. Phys. J. B 71, 37-40 (2009)
https://doi.org/10.1140/epjb/e2009-00269-1

Cross effect of Coulomb correlation and hybridization in the occurrence of ferromagnetism in two shifted band transition metals

¹ Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, Rio de Janeiro, 22290-180 RJ, Brazil
² Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, 20550-013, Rio de Janeiro, RJ, Brazil

Corresponding author: ^a cmch@cbpf.br

Received: 4 February 2009
Revised: 30 June 2009
Published online: 24 July 2009

Abstract

In this work we discuss the occurrence of ferromagnetism in transition-like metals. The metal is represented by two hybridized (V) and shifted (ϵ_s) bands one of which includes Hubbard correlation whereas the other is uncorrelated. The starting point is to transform the original Hamiltonian into an effective one. Only one site retains the full correlation (U) while in the others the correlations are represented by an effective field, the self-energy (single-site approximation). This field is self-consistently determined by imposing the translational invariance of the problem. Thereby one gets an exchange split quasi-particle density of states and then an electron-spin polarization for some values of the parameters (U,V, α, ϵ_s), α being the ratio of the effective masses of the two bands and of the occupation number n.