Intertwined charge, spin, and orbital degrees of freedom under electronic correlations in the one-dimensional Fe3+ chalcogenide chain

Abstract

Motivated by recent developments in the study of quasi-one-dimensional iron systems with Fe2+, we comprehensively study an Fe3+ chalcogenide chain system. Based on first-principles calculations, the Fe3+ chain has a similar electronic structure to that discussed before for the Fe2+ chain, because of the similar Fe⁢𝑋4 (𝑋=S or Se) tetrahedron-chain geometry. Furthermore, a three-orbital electronic Hubbard model for this chain was constructed using the density matrix renormalization group method. A robust antiferromagnetic coupling was unveiled in the chain direction. In addition, in the intermediate electronic correlation 𝑈/𝑊 region, we found an interesting orbital-selective Mott phase with the coexistence of localized and itinerant electrons (𝑈 is the on-site Hubbard repulsion, while 𝑊 is the electronic bandwidth) based on the orbital-selective behavior observed in the charge fluctuations. Furthermore, we do not observe any obvious pairing tendency in the Fe3+ chain in the electronic-correlation 𝑈/𝑊 region, where superconducting pairing tendencies were reported before in iron ladders. This suggests that superconductivity is unlikely to emerge in the Fe3+ systems. Our results clearly establish the similarities and differences between Fe2+ and Fe3+ iron chains, as well as iron ladders.