title: Coulomb repulsion and correlation strength in LaFeAsO from density functional and dynamical mean-field theories.
abstract: The LDA+DMFT (local density approximation combined with dynamical mean-field theory) computation scheme has been used to calculate spectral properties of LaFeAsO-the parent compound of the new high-T(c) iron oxypnictides. The average Coulomb repulsion [Formula: see text] and Hund's exchange J parameters for iron 3d electrons were calculated using the first-principles constrained density functional theory scheme in the Wannier functions formalism. Resulting values strongly depend on the number of states taken into account in the calculations: when the full set of O-2p, As-4p and Fe-3d orbitals and the corresponding bands are included, the interaction parameters [Formula: see text] eV and J = 0.8 eV are obtained. In contrast, when the basis set is restricted to the Fe-3d orbitals and bands only, the calculation gives much smaller values of [Formula: see text] eV, J = 0.5 eV. Nevertheless, DMFT calculations with both parameter sets and the corresponding basis sets result in a weakly correlated electronic structure that is in agreement with the experimental x-ray and photoemission spectra.
authors.affiliation: Institute of Metal Physics, Russian Academy of Sciences, 620041 Yekaterinburg GSP-170, Russia.
authors.forename: V I
authors.initials: VI
authors.lastname: Anisimov
authors.forename: Dm M
authors.initials: DM
authors.lastname: Korotin
authors.forename: M A
authors.initials: MA
authors.lastname: Korotin
authors.forename: A V
authors.initials: AV
authors.lastname: Kozhevnikov
authors.forename: J
authors.initials: J
authors.lastname: Kuneš
authors.forename: A O
authors.initials: AO
authors.lastname: Shorikov
authors.forename: S L
authors.initials: SL
authors.lastname: Skornyakov
authors.forename: S V
authors.initials: SV
authors.lastname: Streltsov