Abstract
The recent discovery of superconductivity at high pressure in the two-leg ladder compounds BaFe2X3(X= S, Se) started the novel field of quasi-one-dimensional iron-based superconductors. In this paper, we use density functional theory (DFT) to predict that the previously barely explored ladder compound RbFe2Te3 should be magnetic with a CX-type arrangement involving ferromagnetic rungs and antiferromagnetic legs, at the realistic density of n=5.5 electrons per iron. The magnetic state similarity with BaFe2S3 suggests that RbFe2Te3 could also become superconducting under pressure. Moreover, at n=6.0 our DFT phase diagrams (with and without lattice tetramerization) reveal that the stable magnetic states could be either a 2×2 magnetic block-type, as for X= Se, or a previously never observed before CY-type state, with ferromagnetic legs and antiferromagnetic rungs. In the Te-based studies, electrons are more localized than in S, implying that the degree of electronic correlation is enhanced for the Te case.
