Effects of disordered Ru substitution in BaFe${}_2$As${}_2$: Realization of superdiffusion mechanism in real materials

Abstract

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.

5 pages, 3 figures, plus supplementary materials