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

TL;DR

This paper investigates the metal-insulator transition in the Hubbard model on various lattices, highlighting the role of magnetic order and electron correlations in the transition, and identifying metallic antiferromagnetic phases in three dimensions.

Contribution

It compares magnetic and non-magnetic scenarios of MIT using advanced methods, revealing the significance of magnetic correlations and the existence of metallic magnetic phases.

Findings

Magnetic scenario of MIT is more accurate than non-magnetic.

Electron correlations suppress spiral phases compared to Hartree-Fock.

Metallic antiferromagnetic phases are found in 3D lattices.

Abstract

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 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.