Pressure-induced electronic phase transition and superconductivity in spin-ladder compounds BaFe₂(S_1−x Se _x )₃

Abstract

The discovery of high-temperature superconductivity in quasi-one-dimensional spin ladder compound BaFe2S3 has attracted great attention for facilitating study on the interplay among crystalline dimensionality, magnetism, and superconductivity. Here, we report a systematic study on the doping-dependent structure, susceptibility, and high-pressure properties of BaFe2(S1−x Se x )3. The structural analysis manifests a structural transition within the doping level of 0.18 < x< 0.29. Accompanied with this structural transition, the magnetic susceptibility behaviors change substantially, in line with the antiferromagnetic structure change from the stripe-type to the block-type. Furthermore, obvious spin glassy behaviors are observed in the low-temperature region for x⩾ 0.29. High-pressure study has revealed an explicit superconductivity signal in the undoped BaFe2S3 with a pressure of about 12.6 GPa, while no bulk superconductivity is observed for the Se-doped samples. Analysis of the pressure-dependent resistance behavior indicates a pressure-induced electronic phase transition around 18 GPa for all Se-doped samples. Finally, we have discussed the possible origin for the pressure-induced superconductivity in BaFe2(S1−x Se x )3.