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Spin degrees of freedom and flattening of the spectra of single-particle excitations in strongly correlated Fermi systems

V. A. Khodel·P. Schuck·M. V. Zverev
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Abstract

The impact of long-range spin-spin correlations on the structure of a flat portion in single-particle spectra $ξ(p)$, which emerges beyond the point, where the Landau state loses its stability, is studied. We supplement the well-known Nozieres model of a Fermi system with limited scalar long-range forces by a similar long-range spin-dependent term and calculate the spectra versus its strength $g$. It is found that Nozieres results hold as long as $g>0$. However, with $g$ changing its sign, the spontaneous magnetization is shown to arise at any nonzero $g$. The increase of the strength $|g|$ is demonstrated to result in shrinkage of the domain in momentum space, occupied by the flat portion of $ξ(p)$, and, eventually, in its vanishing.

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V. A. Khodel, P. Schuck, M. V. Zverev. 2003-08-15. Spin degrees of freedom and flattening of the spectra of single-particle excitations in strongly correlated Fermi systems. https://doi.org/10.1134/1.1619498

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