Possible Kondo effect in the iron arsenides

TL;DR

This paper proposes that the anomalous magnetic and electrical behaviors observed in iron arsenides are due to a Kondo effect arising from interactions between charge carriers and local magnetic moments, coexisting with spin-density waves.

Contribution

It introduces the idea that the Kondo effect may be responsible for the magnetic and resistivity anomalies in iron arsenides, a novel interpretation in this context.

Findings

Linear-T susceptibility observed above SDW transition

Logarithmic resistivity upturn at low temperatures

Change of magnetoresistance from positive to negative

Abstract

The normal state of the iron arsenides shows the poor metallic behavior mixed with strong magnetic fluctuations. In particular, some FeAs-1111 and FeAs-122 compounds show the linear-T dependence of susceptibility above the spin-density wave (SDW) transition and the logarithmic upturn of resistivity at low temperatures. We suggest that this is due to the spin-flip scattering between the charge carriers and the local moments in the undoped FeAs layer where Kondo effect coexists with the SDW. This scenario is also accounted for the change of the magnetoresistance from positive to negative in the Sr3Sc2O5Fe2As2 compound.