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

Abstract

BaFe2S3 is a special iron superconductor with a 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 it has been claimed to be a Mott insulator. Superconductivity emerges under pressure. To analyze the strength of the local correlations in BaFe2S3, we apply the slave-spin technique to a model, which includes the five Fe d orbitals. We find that at zero pressure, BaFe2S3 is strongly correlated. The correlations are particularly severe for the two orbitals with the largest weight at the Fermi level, which show mass enhancements m*∼12–15. Such strong correlations invalidate nesting as the mechanism for AF. We find that the system is not a Mott insulator at zero temperature. Nevertheless these two orbitals will become incoherent at higher temperatures. At the pressure at which the superconductivity appears, the electronic correlations in BaFe2S3 are strongly reduced and similar to the ones measured in other iron superconductors. Different from what happens in other iron superconductors, at both pressures, the Fermi surface is reconstructed by the electronic correlations.

Source-reported materials — not catalogue approval

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