Complex magnetic exchange, anisotropy and skyrmionic textures in 2D ferromagnets with transition metals and chalcogens

Abstract Recently resynthesized FeNbTe 2 has been confirmed to exhibit ferromagnetism. Using first-principles methods, we investigate the magnetic properties of two-dimensional FeXZ 2 ( X = Nb, Ta; Z = S, Se, Te) compounds, including their non-centrosymmetric Janus counterparts. These materials are found to be energetically, dynamically, thermally, and mechanically stable, indicating that FeNbTe 2 can be exfoliated and that new related compounds could be realized experimentally. Analysis of hopping parameters reveals that nearest-neighbor magnetic interactions are primarily direct, while second-nearest and more distant interactions are mediated by chalcogen atoms. Despite their smaller magnitude, second-nearest interactions play a decisive role in magnetic ordering. We identify canted magnetic anisotropy with strong magnetocrystalline anisotropy energy and easy-axis tilts of up to 41 ∘ , an uncommon feature favorable for spintronics. Monte Carlo simulations yield Curie temperatures below room temperature, while micromagnetic simulations predict that Janus FeNbSeTe can host zero-field Néel-type skyrmions, making it a promising target for experiments.