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Antiferromagnetism of almost localized fermions: Evolution from Slater-type to Mott-Hubbard gap

P. Korbel·W. Wójcik·A. Klejnberg·J. Spalek·M. Acquarone·M. Lavagna
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Abstract

We supplement (and critically overview) the existing extensive analysis of antiferromagnetic solution for the Hubbard model with a detailed discussion of two specific features, namely (i) the evolution of the magnetic (Slater) gap (here renormalized by the electronic correlations) into the Mott-Hubbard or atomic gap, and (ii) a rather weak renormalization of the effective mass by the correlations in the half-filled-band case, which contrasts with that for the paramagnetic case. The mass remains strongly enhanced in the non-half-filled-band case. We also stress the difference between magnetic and non-magnetic contributions to the gap. These results are discussed within the slave boson approach in the saddle-point approximation, in which there appears a non-linear staggered molecular field due to the electronic correlations that leads to the appearance of the magnetic gap. They reproduce correctly the ground-state energy in the limit of strong correlations. A brief comparison with the solution in the limit of infinite dimensions and the corresponding situation in the doubly-degenerate-band case with one electron per atom is also made.

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P. Korbel, W. Wójcik, A. Klejnberg, J. Spalek, M. Acquarone, M. Lavagna. 2003-10-28. Antiferromagnetism of almost localized fermions: Evolution from Slater-type to Mott-Hubbard gap. https://doi.org/10.1140/epjb%2Fe2003-00104-9

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