Effects of disordered Ru substitution in BaFe$_2$As$_2$: Realization of   superdiffusion mechanism in real materials
  An unexpected insensitivity of the Fermi surface to impurity scattering is found in Ru substituted BaFe$_2$As$_2$ from first-principles theory, offering a natural explanation of the unusual resilience of transport and superconductivity to a high level of disordered substitution in this material. This robustness is shown to originate from a coherent interference of correlated on-site and inter-site impurity scattering, similar in spirit to the microscopic mechanism of superdiffusion in one dimension. Our result also demonstrates a strong substitution dependence of the Fermi surface and carrier concentration, and provides a natural resolution to current discrepancies in recent photoelectron spectroscopy. These effects offer a natural explanation of the diminishing long-range magnetic, orbital and superconducting order with high substitution. 
Limin Wang, Tom Berlijn, Yan Wang, Chia-Hui Lin, P. J. Hirschfeld, and   Wei Ku
cond-mat.supr-con