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

TL;DR

This paper reveals that Ru substitution in BaFe$_2$As$_2$ maintains Fermi surface stability due to superdiffusion-like impurity scattering, explaining the resilience of its superconducting and magnetic properties despite disorder.

Contribution

It demonstrates a superdiffusion mechanism in a real material, explaining impurity insensitivity and resolving discrepancies in spectroscopic data.

Findings

Fermi surface remains insensitive to impurity scattering in Ru-doped BaFe$_2$As$_2$

Superdiffusion-like interference explains robustness of transport and superconductivity

Substitution significantly affects Fermi surface and carrier concentration

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.