title: First-principles periodic calculation of four-body spin terms in high-Tc cuprate superconductors.
abstract: A general mapping between the energy of pertinent magnetic solutions and the diagonal terms of the spin Hamiltonian in a local representation provides the first general framework to extract accurate values for the many body terms of extended spin Hamiltonians from periodic first-principle calculations. Estimates of these terms for La2CuO4, the paradigm of high-Tc superconductor parent compounds, and for the SrCu2O3 ladder compound are reported. For La2CuO4, present results support experimental evidence by Toader et al. [Phys. Rev. Lett. 94, 197202 (2005)10.1103/PhysRevLett.94.197202]. For SrCu2O3 even larger four-body spin amplitudes are found together with Jl/Jr = 1 and non-negligible ferromagnetic interladder exchange.
authors.affiliation: Departament de Química Física and Centre Especial de Recerca en Química Teòrica, Universitat de Barcelona and Parc Científic de Barcelona, C/ Martí i Franquès 1, E-08028 Barcelona, Spain.
authors.forename: Ibério de P R
authors.initials: Ide P
authors.lastname: Moreira
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Calzado
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Malrieu
authors.forename: Francesc
authors.initials: F
authors.lastname: Illas