Sparse Pd-Te Covalent Bridges Drive Anomalous Bulk-to-Monolayer Electronic and Magnetic Evolution in FePd2Te2.

Non-van-der-Waals (non-vdW) layered magnets provide bonding degrees of freedom beyond dispersion-dominated stacks, yet how dilute interlayer covalent bridges influence bulk-to-monolayer evolution remains insufficiently understood. Using first-principles calculations, we investigate FePd2Te2 (FPT), a layered ferromagnet with sparse interlayer Pd─Te bridges. These bridges exhibit a covalent component, while the cleavage energy remains in the vdW-like range (∼0.51 J·m-2), establishing FPT as an exfoliable non-vdW layered magnet. Upon thinning from bulk to monolayer, local Fe moments and intralayer exchange terms increase slightly, whereas the Curie temperature decreases from 173 to 27 K. Analysis of multiplicity-weighted exchange contributions indicates that this suppression of TC is governed primarily by the weakening and eventual disappearance of interlayer ferromagnetic exchange J3, with enhanced antiferromagnetic competition from J2 providing an additional destabilizing contribution. Meanwhile, orbital reorganization near the Fermi level sustains a relatively large easy-plane magnetocrystalline anisotropy (∼1.86 meV per Fe in bulk) with a moderate enhancement (∼8.6%) in the monolayer, gives rise to a dimensionality-dependent reversal of magnetoelastic response under biaxial strain, and leaves the near-EF spin polarization comparatively robust up to ±5% strain. These results identify FPT as a representative exfoliable non-vdW magnet and clarify how sparse interlayer covalent bridges govern its thickness-dependent magnetic evolution.