Interplay of Magnetic Order, Structural Stability, and Orbital Ordering in BaFe2X3 (X = S and Se)

Abstract: BaFe2X3 (X= S and Se) are quasi-one-dimensional Mott insulators with a ladder structure that exhibit Stripe- and Block-type antiferromagnetic order, respectively. The ladder arrangement of Fe atoms and strong electron correlations give rise to rich magnetic and orbital phenomena, including pressure-induced superconductivity and orbital-selective electronic states. Both compounds also show resistivity anomalies above the Neel temperature, suggesting that orbital degrees of freedom play an important role in their electronic properties. To clarify the interplay among magnetic order, structural stability, orbital ordering, and transport properties, we performed resistivity measurements and first-principles calculations for BaFe2S3 and BaFe2Se3, systematically comparing candidate magnetic and crystal structures. We find that the magnetic configuration strongly influences the stable crystal structure, orbital ordering, and transport anisotropy, providing a microscopic understanding of the contrasting electronic properties of the two compounds.