HARTREE-FOCK STUDY OF THE MAGNETISM IN THE SINGLE-BAND HUBBARD-MODEL

We study the magnetic phases of the single-band Hubbard model within the self-consistent Hartree-Fock formalism applied to a large supercell. We find that incommensurate spin-density waves gradually deform into domain walls with increasing correlation energy U, in agreement with previous studies. For U/t > 8 the domain walls evaporate into separated magnetic polarons. For U/t < 20, the spin expectation values are collinear. However, we find clear evidence for the importance of the transverse spin components in the large-correlation limit, although the exact ground state cannot be determined. The connection between the resulting band structures and photoabsorption and optical data is discussed.