Coulomb repulsion and correlation strength in LaFeAsO from Density Functional and Dynamical Mean-Field Theories

Abstract

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 for new high-T${}_c$ iron oxypnictides. Coulomb repulsion $U$ and Hund's exchange $J$ parameters for iron 3d electrons were calculated using \textit {first principles} constrained density functional theory scheme in Wannier functions formalism. Resulting values strongly depend on the number of states taken into account in calculations: when full set of O-$2p$, As-$4p$, and Fe-3d orbitals with corresponding bands are included, computation results in $U=3÷$4 eV and J=0.8 eV. In contrast to that when the basis set is restricted to Fe-3d orbitals and bands only, computation gives much smaller parameter values $F^0$=0.8 eV, $J$=0.5 eV. However, DMFT calculations with both parameter sets and corresponding to them choice of basis functions result in weakly correlated electronic structure that is in agreement with experimental X-ray and photoemission spectra.

13 pages, 9 figures

References in corpus (3)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Construction and solution of a Wannier-functions based Hamiltonian in the pseudopotential plane-wave framework for strongly correlated materials
• Physics of cuprates with the two-band Hubbard model - The validity of the one-band Hubbard model

Cited by in corpus (5)

• Dynamical Mean-Field Theory within an Augmented Plane-Wave Framework: Assessing Electronic Correlations in the Iron Pnictide LaFeAsO
• Electronic Structure of Fe-Based Superconductors
• Classification of the electronic correlation strength in the Fe-pnictides: The case of the parent compound BaFe2As2
• Optical Properties of Correlated Materials -- or Why Intelligent Windows may look Dirty
• Correlated electrons in Fe-As compounds: a quantum chemical perspective