First-principles calculations of the exchange coupling constants in La2CuO4

Abstract: The exchanging coupling mechanism for has been studied by employing unrestricted Hartree-Fock (UHF) and configuration interaction method. The coupling constant was calculated by using copper cluster models. It is shown that exchange interactions between the orbitals play a very important role in the exchange coupling of and O to excitations have secondary important in the ground state. The coupling constant calculated in this work was in good agreement with the experimental value. [Copyright &y& Elsevier]