Title: Metallic ferromagnetism in the systems with strongly correlated electrons
Authors:

	L.Didukh (Ternopil State Technical University, Department of Physics, 56 Ruska Str., 46001 Ternopil, Ukraine) ,
	O.Kramar (Ternopil State Technical University, Department of Physics, 56 Ruska Str., 46001 Ternopil, Ukraine)

The present paper considers the ground state ferromagnetic ordering in narrow-band models with strongly correlated electrons, in particular, in a single-band generalized Hubbard model with correlated hopping and interatomic exchange interaction, as well as in a double orbitally degenerate Hubbard model with correlated hopping. The effective Hamiltonians of these models are treated by means of variants of generalized Hartree-Fock approximations, in which the quasi-particle energy spectra are obtained. The ground state energy, critical electron concentration and magnetization are calculated for some types of density of states. The mechanisms of ferromagnetic ordering stability in the narrow-band materials are discussed.

Key words: narrow energy band, ferromagnetism, ground state energy, magnetization
PACS: 71.10.Fd, 75.10.-b, 75.20.En