Satellites and large doping and temperature dependence of electronic properties in hole-doped BaFe ₂As ₂

Superconductivity has recently been discovered in several families of iron-based compounds, but despite intense research even such basic electronic properties of these materials as Fermi surfaces, effective electron masses and orbital characters are still subject to debate. Here, we address an issue that has not been considered before, namely the consequences of dynamical screening of the Coulomb interactions between Fe d electrons. We demonstrate that dynamical screening effects are important not only for higher-energy spectral features, such as correlation satellites seen in photoemission spectroscopy, but also for the low-energy electronic structure. Our analysis indicates that BaFe ₂As ₂ is a strongly correlated compound with strongly doping- and temperature-dependent properties. In the hole-overdoped regime an incoherent metal is found, whereas Fermi-liquid behaviour is recovered in the undoped compound. At optimal doping, the self-energy exhibits an unusual square-root energy dependence, which leads to strong band renormalizations near the Fermi level.