FeTaX_{2}: A Ferrimagnetic Quantum Anomalous Hall Insulator.

We propose the van der Waals layered ternary transition metal chalcogenides FeTaX_{2} (X=S, Se, Te) as a new family of ferrimagnetic quantum anomalous Hall insulators with a sizable bulk gap and high Chern number C=-2. The magnetic order arises primarily from Fe atoms, whose strong ferromagnetic exchange induces moments on neighboring Ta sites. The large topological gap originates from a strong s-d-type band inversion between spin-down Ta d_{z^{2}} and d_{xy} orbitals near the Fermi level-a mechanism unique to d-orbital systems. Remarkably, the Curie temperature of monolayer FeTaX_{2} is predicted to significantly exceed that of monolayer MnBi_{2}Te_{4}. Furthermore, both the Curie temperature and topological gap scale positively with the spin-orbit coupling strength of the d electrons, suggesting a common physical origin. These findings, if realized experimentally, could open new avenues for the research and application of topological quantum physics.