Water-induced superconductivity in SrFe2As2

TL;DR

Exposure to water vapor can induce superconductivity in undoped SrFe2As2 thin films, achieving higher transition temperatures and different mechanisms than traditional doping methods, offering a new pathway for high-Tc superconductor development.

Contribution

This study demonstrates water vapor exposure as a novel method to induce superconductivity in undoped SrFe2As2 films, differing from conventional doping techniques.

Findings

Superconductivity induced by water vapor in undoped SrFe2As2.

Higher onset-Tc (25 K) compared to doped counterparts.

Distinct magnetic anisotropy indicating a different mechanism.

Abstract

It has been considered that FeAs-based high transition temperature (high-Tc) superconductors need electron or hole doping by aliovalent ion substitution or large off-stoichiometry in order to induce superconductivity. We report that exposure of undoped SrFe2As2 epitaxial thin films to water vapor induces a superconducting transition. These films exhibit a higher onset-Tc (25 K) and larger magnetic field anisotropy than those of cobalt-doped SrFe2As2 epitaxial films, suggesting that the mechanism for the observed superconducting transition differs from that of the aliovalent-ion doped SrFe2As2. The present finding provides a new approach to induce superconductivity with a higher Tc in FeAs-based superconductors.