Electron doping of the iron-arsenide superconductor CeFeAsO controlled by hydrostatic pressure

TL;DR

This study investigates how hydrostatic pressure influences electron doping and magnetic interactions in CeFeAsO, revealing a complex interplay between magnetic order suppression, Kondo screening, and superconductivity emergence.

Contribution

It demonstrates the pressure-controlled transition from magnetic order to superconductivity and highlights the role of Ce-4f moments and Kondo effects in this process.

Findings

Pressure suppresses Fe SDW order up to 4 GPa.

Superconductivity appears after magnetic orders vanish.

Kondo-lattice behavior becomes prominent at higher pressures.

Abstract

In the iron-pnictide material CeFeAsO not only the Fe moments, but also the local 4f moments of the Ce order antiferromagnetically at low temperatures. We elucidate on the peculiar role of the Ce on the emergence of superconductivity. While application of pressure suppresses the iron SDW ordering temperature monotonously up to 4 GPa, the Ce-4f magnetism is stabilized, until both types of magnetic orders disappear abruptly and a narrow SC dome develops. With further increasing pressure characteristics of a Kondo-lattice system become more and more apparent in the electrical resistivity. This suggests a connection of the emergence of superconductivity with the extinction of the magnetic order and the onset of Kondo-screening of the Ce-4f moments.