Pressure-induced Superconductivity in the Iron-based Ladder Material BaFe2S3

TL;DR

This paper reports the discovery of pressure-induced superconductivity in the iron-based ladder material BaFe2S3, expanding the understanding of iron-based superconductors beyond square lattice structures and highlighting the potential of ladder compounds.

Contribution

It is the first to demonstrate superconductivity in an iron-based ladder compound under pressure, revealing new structural motifs for superconductivity research.

Findings

Superconductivity appears at 14 K under 11 GPa pressure.

BaFe2S3 transitions from insulator to metal before superconductivity.

Superconductivity occurs in a non-square lattice iron-based material.

Abstract

All the iron-based superconductors identified to date share a square lattice composed of Fe atoms as a common feature, despite having different crystal structures. In copper-based materials, the superconducting phase emerges not only in square lattice structures but also in ladder structures. Yet iron-based superconductors without a square lattice motif have not been found despite being actively sought out. Here, we report the discovery of pressure-induced superconductivity in the iron-based spin-ladder material BaFe2S3, a Mott insulator with striped-type magnetic ordering below ~120 K. On the application of pressure this compound exhibits a metal-insulator transition at about 11 GPa, followed by the appearance of superconductivity below Tc = 14 K, right after the onset of the metallic phase. Our findings indicate that iron-based ladder compounds represent promising material platforms, in particular for studying the fundamentals of iron-based superconductivity.