Antiferromagnetism ofCuO2layers within a slave-boson approach

The antiferromagnetic ground state of ${\mathrm{CuO}}_2$ layers is studied at the mean-field level within a slave-boson approach to a multiband Hubbard model which includes the ${\mathit{d}}_{\mathit{x}}^2$-${\mathit{y}}^2$ orbital for Cu and the ${\mathit{p}}_{\mathit{x}}$ and ${\mathit{p}}_{\mathit{y}}$ orbitals for O. The stability of the antiferromagnetism is tested by varying the separation Δ between p- and d-hole energy levels and by allowing direct O-O hopping. Results for the effective exchange integral, the antiferromagnetic gap, the percentage of d character of holes at the Fermi level, and the Cu magnetic moment are discussed by varying Δ.