Metallic ferromagnetism in a generalized Hubbard model

Didukh, L.; Kramar, Oleksandr

doi:10.1063/1.1449182

Cited by 7 publications

(2 citation statements)

References 27 publications

(89 reference statements)

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“…[9][10][11][12][13]), where the authors used other methods to treat electron correlations in less complicated Hamiltonians, and are in agreement with experimental data. In particular, the approach we use allows us to avoid the problem of Curie temperature overestimation, and to explain the peculiarities of ferromagnetic properties (electron-hole asymmetry of the concentration dependence of magnetization and of Curie temperature) for some transition metals and their compounds (in this connection see [18], and also section 2).…”

Section: J (Iγ Kγ Jγ Kγ )mentioning

confidence: 99%

Itinerant ferromagnetism of systems with double orbital degeneracy

Didukh

Hankevych

Kramar

et al. 2002

J. Phys.: Condens. Matter

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In this paper we study the ground state ferromagnetism in a doubly orbitally degenerate Hubbard model generalized by taking into account correlated hopping and inter-atomic exchange interaction. We find that an important role in the stabilization of ferromagnetism is played by the intra- and inter-atomic exchange interactions as well as correlated hopping, which allows us to describe the metallic paramagnetic-ferromagnetic transition with a realistic relationship between the above-mentioned exchange interactions. The expression for magnetization and the criterion of ferromagnetic ground state stability are derived. The obtained results are compared with some experimental data for magnetic materials.

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Section: J (Iγ Kγ Jγ Kγ )mentioning

confidence: 99%

Itinerant ferromagnetism of systems with double orbital degeneracy

Didukh

Hankevych

Kramar

et al. 2002

J. Phys.: Condens. Matter

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“…For n > 1 we obtainẼ s in a similar form; expressions for correlation narrowing factor and shift of subband center are obtained from equations (16) and (17) replacing n → 2 − n, t(n) →t(n). The analytical calculation of spin-dependent shift of the subband center β s for model rectangular density of states (DOS) has been done in the work [35]. In the present paper β s is calculated numerically and its value is shown to depend drastically on non-perturbed DOS form.…”

Section: Ferromagnetic Ordering In the Modelmentioning

confidence: 99%

Electron correlations in narrow energy bands: modified polar model approach

Didukh¹,

Skorenkyy²,

Kramar³

2008

Condens. Matter Phys.

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The electron correlations in narrow energy bands are examined within the framework of the modified form of polar model. This model permits to analyze the effect of strong Coulomb correlation, inter-atomic exchange and correlated hopping of electrons and explain some peculiarities of the properties of narrow-band materials, namely the metal-insulator transition with an increase of temperature, nonlinear concentration dependence of Curie temperature and peculiarities of transport properties of electronic subsystem. Using a variant of generalized Hartree-Fock approximation, the single-electron Green's function and quasi-particle energy spectrum of the model are calculated. Metal-insulator transition with the change of temperature is investigated in a system with correlated hopping. Processes of ferromagnetic ordering stabilization in the system with various forms of electronic DOS are studied. The static conductivity and effective spin-dependent masses of current carriers are calculated as a function of electron concentration at various DOS forms. The correlated hopping is shown to cause the electron-hole asymmetry of transport and ferromagnetic properties of narrow band materials.

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