A theory, based on a generalized Hartree-Fock scheme, is developed, giving both the atomic and the metallic limit of the Hubbard model correctly. In the strong coupling case an insulating state having localized moments is obtained, and an effective Heisenberg Hamiltonian describing the coupling between these moments is deduced. The coupling is antiferromagnetic and a Neel temperature of the order of t2/U is obtained, t representing the hopping matrix elements, U the Coulomb repulsion. Both the magnetically ordered and the magnetically disordered states are insulating having localized moments. Comparison with the functional integral method is made. The qualitative aspects of the theory are applicable to some transition metal oxides (NiO and MnO for example).
No takes yet. Share an insight, caveat, or question.
H. Capellmann (1974) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: