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On the derivation of the t-J model: electron spectrum and exchange interactions in narrow energy bands

V. Yu. Irkhin
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Abstract

A derivation of the t-J model of a highly-correlated solid is given starting from the general many-electron Hamiltonian with account of the non-orthogonality of atomic wave functions. Asymmetry of the Hubbard subbands (i.e. of ``electron'' and ``hole''cases) for a nearly half-filled bare band is demonstrated. The non-orthogonality corrections are shown to lead to occurrence of indirect antiferromagnetic exchange interaction even in the limit of the infinite on-site Coulomb repulsion. Consequences of this treatment for the magnetism formation in narrow energy bands are discussed. Peculiarities of the case of ``frustrated'' lattices, which contain triangles of nearest neighbors, are considered.

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V. Yu. Irkhin. 1997-05-06. On the derivation of the t-J model: electron spectrum and exchange interactions in narrow energy bands. https://doi.org/10.1103/physrevb.57.13375

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