Superconductivity induced by doping Ru in SrFe2-xRuxAs2

TL;DR

This study demonstrates that doping Ru into SrFe2As2 induces superconductivity by suppressing SDW transition, with a maximum Tc of 13.5 K at a specific doping level, highlighting the role of isoelectronic substitution.

Contribution

It provides experimental evidence that isoelectronic Ru doping can induce superconductivity in SrFe2As2, expanding understanding of doping effects in iron-based superconductors.

Findings

Superconductivity appears at Ru doping level x=0.7.

Maximum Tc of 13.5 K observed at x=0.7.

Ru doping suppresses SDW transition and induces superconductivity.

Abstract

Using one-step solid state reaction method, we have successfully synthesized the superconductor SrFe1-xRuxAs. X-ray diffraction indicates that the material has formed the ThCr2Si2-type structure with a space group I4/mmm. The systematic evolution of the lattice constants demonstrates that the Fe ions are successfully replaced by the Ru. By increasing the doping content of Ru, the spin-density-wave (SDW) transition in the parent compound is suppressed and superconductivity emerges. The maximum superconducting transition temperature is found at 13.5 K with the doping level of x = 0.7. The temperature dependence of DC magnetization confirms superconducting transitions at around 12 K. Our results indicate that similar to non-isoelectronic substitution, isoelectronic substitution contributes to changes in both the carrier concentration and internal pressure, and superconductivity could be induced by isoelectronic substitution.