V I Anisimov et al 2009 J. Phys.: Condens. Matter 21 075602 doi:10.1088/0953-8984/21/7/075602
V I Anisimov1, Dm M Korotin1, M A Korotin1, A V Kozhevnikov1,2, J Kuneš3,4, A O Shorikov1, S L Skornyakov1 and S V Streltsov1
Show affiliationsThe 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-Tc iron oxypnictides. The average Coulomb repulsion
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
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
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.
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
74.70.Dd Ternary, quaternary and multinary compounds (including Chevrel phases, borocarbides, etc.)
Issue 7 (18 February 2009)
Received 15 October 2008, in final form 3 December 2008
Published 20 January 2009
V I Anisimov et al 2009 J. Phys.: Condens. Matter 21 075602
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