Comparison of the electronic structure of La/sub 2/CuO/sub 4/, La/sub 2/NiO/sub 4/, and K/sub 2/CuF/sub 4/

We report local density calculations of parameters defining extended Hubbard Hamiltonians for La/sub 2/CuO/sub 4/, La/sub 2/NiO/sub 4/, and K/sub 2/CuF/sub 4/, and solve these models for small clusters. These results suggest qualitative differences among the three compounds in regard to spin system, carriers, and carrier --- spin interactions. 6 refs., 2 tabs.