Magnetic impurities in the two-band $s_\pm$-wave superconductors

TL;DR

This paper studies how magnetic impurities affect $s_$-wave superconductors with two bands, revealing that intra-band scattering breaks pairs while inter-band scattering preserves superconductivity, aligning with experiments on iron-based materials.

Contribution

It demonstrates the distinct roles of intra- and inter-band magnetic scattering in $s_$-wave superconductors within a two-band model, supporting the $s_$ pairing symmetry hypothesis.

Findings

Intra-band magnetic scattering acts as a pair breaker.

Inter-band magnetic scattering minimally affects transition temperature.

Results align with experimental data on iron-based superconductors.

Abstract

We investigate the effects of magnetic impurities in a superconducting state with $s_\pm$ pairing symmetry. Within a two-band model, we find that the intra-band magnetic scattering serves as a pair breaker while the inter-band magnetic scattering preserves pairing and hardly affects transition temperature in the Born limit. We also show that the same physics can persist beyond the weak scattering region. Our results coincide with recent experimental measurements in iron-based superconductors and thus provides an indirect evidence of the possible $s_\pm$ pairing symmetry in these materials.