Calculation of Parameters for the Extended Hubbard Model of High T sub c Cu-Oxide Superconductors

An internally consistent set of parameters for the extended, three band Hubbard model of the Cu-O sheets has been calculated from first principles using a constrained density functional approach [1]. The local density functional energy surface as a function of local charge fluctuations in La sub 2 CuO sub 4 is mapped onto a self consistent mean field solution of the Hubbard model which allows extraction of the Coulomb interaction parameters when combined with one-electron parameters derived from band structure results.