Strong electronic correlations and Fermi surface reconstruction in the quasi-one dimensional iron superconductor BaFe2S3

TL;DR

This study investigates the electronic correlations and Fermi surface changes in BaFe2S3, revealing enhanced correlations at zero pressure and Fermi surface reconstruction driven by correlations, which differ from other iron superconductors.

Contribution

It provides new insights into the correlation strength and Fermi surface evolution in BaFe2S3, highlighting differences from other iron superconductors and the role of electronic correlations.

Findings

Correlations are strongly enhanced at zero pressure.

Fermi surface is reconstructed by electronic correlations.

Superconductivity emerges under pressure with similar correlation strength to other iron superconductors.

Abstract

BaFe2S3 is a special iron superconductor with two-leg ladder structure which can help to unravel the role played by the electronic correlations in high-Tc superconductivity. At zero pressure it is insulating with stripe antiferromagnetic (AF) order and superconductivity emerges under pressure. We use a slave-spin technique to analyze the strength of the local correlations in BaFe2S3. We find that at the pressure at which the superconductivity appears the electronic correlations in BaFe2S3 are similar to the ones measured in other iron superconductors. However, at zero pressure the strength of the correlations is strongly enhanced, being particularly severe for the two orbitals with the largest weight at the Fermi level what invalidates nesting as the mechanism for AF. The system is not a Mott insulator at zero temperature, but these two orbitals with mass enhancements m* ~ 12-15 will become incoherent at higher temperatures. Different from what happens in other iron superconductors, at both pressures, the Fermi surface is reconstructed by the electronic correlations.