Influence of Spin-wave excitations on the ferromagnetic phase diagram in the Hubbard model
Journal
Physical Review B
ISSN
0556-2805
ISSN-Digital
1550-235X
Type
journal article
Date Issued
2002-11-04
Author(s)
Rumsch, Wolf
;
Nolting, Wolfgang
Abstract
The subject of the present paper is the theoretical description of collective electronic excitations, i.e., spin waves, in the Hubbard model. Starting with the widely used random-phase approximation, which combines Hartree-Fock theory with the summation of the two-particle ladder, we extend the theory to a more sophisticated single particle approximation, namely, the spectral-density ansatz. Doing so we have to introduce a "screened" Coulomb interaction rather than the bare Hubbard interaction in order to obtain physically reasonable spinwave dispersions. The discussion following the technical procedure shows that comparison of standard RPA with our new approximation reduces the occurrence of a ferromagnetic phase further with respect to the phase diagrams delivered by the single particle theories.
Language
English
Keywords
Strongly Correlated Electrons
HSG Classification
not classified
Refereed
Yes
Publisher
The American Physical Society APS
Publisher place
Ridge, NY
Volume
66
Number
19
Start page
195109
End page
196116
Pages
1008
Subject(s)
Division(s)
Eprints ID
41021