Orbital-selective Mott Physics, block magnetic states, and ferromagnetism in iron chain systems

Investigating the magnetic and orbital-selective physics in iron-based compounds is an active area in condensed matter field. Here, we systematically studied the quasi-one-dimensional iron chain Ce2O2FeSe2 based on a multiorbital Hubbard model using the most accurate many-body numerical methods, the density matrix renormalization-group (DMRG) technique. The complex interplay of hopping amplitudes, Coulomb interactions, Hund’s coupling, crystal-field splitting, and doping effects provide a rich playground for the competition between many tendencies. Firstly, our studies showed that large interorbital hoppings between doubly- and half-filled orbitals play a key role in stabilizing the insulating ferromagnetic phase [1]. Secondly, with the effect of doping and the crystal-field splitting, a variety of exotic electronic and magnetic states, such as ferromagnetic Mott insulating, orbital-selective Mott phases and magnetic “block” phases, were predicted due to the competition between plethora of tendencies [2, 3]. Our theoretical phase diagram will hopefully provide design strategies for exploring 1D iron chalcogenide compounds, or related systems.

[1] L.-F. Lin, et al., Phys. Rev. Lett. 127, 077204 (2021).

[2] L.-F. Lin, et al., Phys. Rev. B 105, 075119 (2022).

[3] L.-F. Lin, et al., Commun. Phys. 6, 199 (2023).