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 ′ Hubbard model at half-filling by using both the generalized for the case of spiral order Hartree–Fock approximation (HFA) and Kotliar–Ruckenstein slave-boson approach. It turns out that the magnetic scenario of MIT becomes superior over the non-magnetic one. The electron correlations lead to some suppression of the spiral phases in comparison with HFA. We found the presence of a metallic antiferromagnetic (spiral) phase in the case of three-dimensional lattices.