Spiral magnetic states in the large-U Hubbard model: a slave boson approach

Abstract

The authors determine the ground state phase diagram of the Hubbard model on the square lattice allowing for homogeneous spiral, antiferromagnetic, ferromagnetic and paramagnetic phases. This is obtained from a saddle-point approximation of a spin-rotation-invariant form of the slave boson representation introduced by Kotliar and Ruckenstein. They obtain very good agreement in energy with exact diagonalization calculations and, concerning the magnetic structure, qualitative agreement with experimental data.