First principles calculations of solute-hole interactions in the high T<sub>c</sub> oxyfluoride superconductor Sr<sub>2</sub>CuO<sub>2</sub>F<sub>2</sub>
First principles periodic Hartree-Fock calculations are reported of the electronic and magnetic structures and hole states in the T (La2CuO4) phases of Sr2CuO2F2, Sr2CuO2F2.5 and NaSrCuO2F2. Sr2CuO2F2 is predicted to be a highly ionic antiferromagnetic charge transfer insulator with Cu in a d(9) ((d(x2-y2))(1)) configuration. Holes are predicted to be highly localised spin polarons which destroy the AF ordering at concentrations of 0.5 per formula unit.</p
