Exact results on ferromagnetism in correlated electron systems

Journal Article · Mon May 01 00:00:00 EDT 1995 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00752314· OSTI ID:107620

Strack, R; Vollhardt, D ^[1]

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1. Institut fuer Theoretische, Aachen (Germany)

Exact results, both old and new, on the stability of saturated ferromagnetism in the Hubbard model and its extension are discussed. For the Hubbard model with all nearest-neighbor interactions a new set of rigorous criteria, valid at half filling, is derived and a generalization of Nagaoka`s theorem to finite interactions is presented. Of all coupling parameters only the on-site and the exchange interaction are found to be essential. At strong coupling comparison with the effective t-J model is made. Further extensions, e.g. to the band-degenerate case, are discussed.

• Sponsoring Organization: USDOE
• OSTI ID: 107620
• Report Number(s): CONF-9409365-; ISSN 0022-2291; TRN: 95:021330
• Journal Information: Journal of Low Temperature Physics, Vol. 99, Issue 3-4; Conference: International Euroconference on magnetic correlations, metal-insulator-transitions, and superconductivity in novel materials, Wuerzburg (Germany), 26-30 Sep 1994; Other Information: PBD: May 1995
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
FERROMAGNETISM
HUBBARD MODEL
ELECTRON CORRELATION
SUPERCONDUCTIVITY