Random Phase Approximation for Multi-Band Hubbard Models
نویسندگان
چکیده
We derive the random-phase approximation for spin excitations in general multi-band Hubbard models, starting from a collinear ferromagnetic HartreeFock 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. PACS numbers: 71.10.Fd, 75.10.Lp, 75.30.Ds Typeset using REVTEX 1
منابع مشابه
Ferromagnetism and Superconductivity in Two-band Hubbard Models
s of Doctor′s Theses (Received The Degree of Doctorof Engineering in 2006) ..................................................................................................................................................................... 24 Abstracts of Papers (Published in 2006) ....................................................................................................................
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تاریخ انتشار 2001