Normal-state correlated electronic structure of iron pnictides from first principles

Abstract

We describe the correlated electronic structure of a prototype Fe-pnictide superconductor, ${\text{SmO}}_{1\ensuremath{-}x}{\text{F}}_{x}\text{FeAs}$, using local-density approximation plus dynamical mean-field theory. Strong, multiorbital electronic correlations generate a low-energy pseudogap in the undistorted phase, giving a bad, incoherent metal in qualitative agreement with observations. Very good semiquantitative agreement with the experimental spectral functions is seen (for $U=4.0\text{ }\text{eV}$ and ${J}_{H}=0.7\text{ }\text{eV}$) and interpreted within a correlated, multiorbital picture. Our results show that Fe pnictides should be understood as low-carrier density, incoherent metals, in resemblance to the underdoped cuprate superconductors.