Pressure Effects on the Superconducting and Spin-Density-Wave States of the Newly Discovered Sm(O1-xFx)FeAs

TL;DR

This study investigates how pressure influences the superconducting transition temperature and spin-density-wave states in Sm(O1-xFx)FeAs, revealing that pressure effects depend on doping levels and suggesting potential for higher Tc in related compounds.

Contribution

It demonstrates that pressure can either suppress or enhance Tc in Sm(O1-xFx)FeAs depending on doping, challenging previous assumptions and guiding future superconductor development.

Findings

Pressure effects on Tc vary with doping level.

Pressure can both suppress and enhance superconductivity.

Potential to achieve Tc in the 50s K in related compounds.

Abstract

High temperature superconductors with a Tc above 40 K have been found to be strongly correlated electron systems and to have a layered structure. Guided by these rules, Kamihara et al. discovered a Tc up to 26 K in the layered La(O1-xFx)FeAs. By replacing La with tri-valence rare-earth elements RE of smaller ionic radii, Tc has subsequently been raised to 41-52 K. Many theoretical models have been proposed emphasizing the important magnetic origin of superconductivity in this compound system and a possible further Tc-enhancement in RE(O1-xFx)FeAs by compression. This later prediction appears to be supported by the pressure-induced Tc-increase in La(O0.89F0.11)FeAs observed. Here we show that, in contrast to previous expectations, pressure can either suppress or enhance Tc, depending on the doping level, suggesting that a Tc exceeding 50's K may be found only in the yet-to-be discovered compound systems related to but different from R(O1-xFx)FeAs and that the Tc of La(O1-xFx)FeAs and Sm(O1-xFx)FeAs may be further raised to 50's K.