Structural and magnetic phase diagram of CeFeAsO1-xFx and its relationship to high-temperature superconductivity

TL;DR

This study investigates how structural and magnetic phase transitions in CeFeAsO1-xFx evolve with fluorine doping, revealing a phase diagram similar to cuprates and emphasizing the role of electron correlations in high-temperature superconductivity.

Contribution

It provides detailed neutron scattering data on phase transitions in CeFeAsO1-xFx, linking structural evolution to superconductivity and highlighting the importance of electron correlations.

Findings

Structural transition decreases with doping

Antiferromagnetic order is suppressed before superconductivity appears

Electronic bandwidth decreases with higher Tc

Abstract

We use neutron scattering to study the structural and magnetic phase transitions in the iron pnictides CeFeAsO1-xFx as the system is tuned from a semimetal to a high-transition-temperature (high-Tc) superconductor through Fluorine (F) doping x. In the undoped state, CeFeAsO develops a structural lattice distortion followed by a stripe like commensurate antiferromagnetic order with decreasing temperature. With increasing Fluorine doping, the structural phase transition decreases gradually while the antiferromagnetic order is suppressed before the appearance of superconductivity, resulting an electronic phase diagram remarkably similar to that of the high-Tc copper oxides. Comparison of the structural evolution of CeFeAsO1-xFx with other Fe-based superconductors reveals that the effective electronic band width decreases systematically for materials with higher Tc. The results suggest that electron correlation effects are important for the mechanism of high-Tc superconductivity in these Fe pnictides.