Metal-Insulator Transition in the Hubbard Model: Correlations and Spiral Magnetic Structures

The metal–insulator transition (MIT) for the square, simple cubic, and body-centered cubic lattices is investigated within the $t-t^{\mathrm{\prime }}$ Hubbard model at half-filling by using both the Hartree-Fock approximation (HFA) generalized for the case of spiral order and Kotliar-Ruckenstein slave-boson approach. It turns out that magnetic scenario of MIT becomes superior over non-magnetic one. The electron correlations lead to some suppression of the spiral phases in comparison with HFA. We found the presence of metallic antiferromagnetic (spiral) phase in the case of three-dimensional lattices.