Abstract:
Constrained density functional theory scheme in Wannier functions formalism has been used to calculate Coulomb repulsion U and Hund's exchange J parameters for Fe-3d electrons in LaFeAsO. Results strongly depend on the basis set. When O-2p, As-4p, and Fe-3d orbitals are included, computation results in U=3÷4 eV. With the basis set restricted to Fe-3d orbitals only, computation gives parameters corresponding to F0=0.8 eV, J=0.5 eV. Local Density Approximation combined with Dynamical Mean-Field Theory calculation with these parameters results in weakly correlated electronic structure.
Citation:
V. I. Anisimov, Dm. M. Korotin, S. V. Streltsov, A. V. Kozhevnikov, J. Kuneš, A. O. Shorikov, M. A. Korotin, “Density-functional calculation of the Coulomb repulsion and correlation strength in superconducting LaFeAsO”, Pis'ma v Zh. Èksper. Teoret. Fiz., 88:11 (2008), 844–848; JETP Letters, 88:11 (2008), 729–733