Magnetic ground state of coupled edge-sharing CuO2 spin chains

By means of density functional theory, we investigate the magnetic ground state of edge-sharing CuO(2) spin chains, as found in the (La,Ca,Sr)(14)Cu(24)O(41) system, for instance. Our data rely on spin-polarized electronic structure calculations including on-site interaction [local density approximation plus the multiorbital mean-field Hubbard model (LDA+U)] and an effective model for the interchain coupling. Strong doping dependence of the magnetic order is characteristic for edge-sharing CuO(2) spin chains. We determine the ground state magnetic structure as function of the spin-chain filling and quantify the competing exchange interactions.