Strain and charge-doping control of perpendicular magnetic anisotropy and Curie temperature in monolayer Fe3SiTe2

Two-dimensional (2D) van der Waals ferromagnets with strong perpendicular magnetic anisotropy and tunable magnetic stability are important for scaled spintronic devices. In this work, we investigate monolayer Fe3SiTe2 using first-principles calculations and atomistic Monte Carlo simulations, with emphasis on the effect of biaxial strain and charge doping on magnetic anisotropy, exchange interactions, and Curie temperature. Pristine Fe3SiTe2 is found to be dynamically stable, metallic, and spin-polarized, with a large positive magnetic anisotropy energy of approximately 1.67 meV/Fe, confirming an out-of-plane easy axis. Atom-resolved magnetocrystalline anisotropy energy (MAE) analysis shows that the Fe/Si-centered layer contributes constructively to the perpendicular anisotropy. Under biaxial strain, the out-of-plane easy axis is preserved over the full strain range from −4% to +4%. In contrast, tensile strain enhances the Curie temperature by making the in-plane exchange interactions less antiferromagnetic. Moreover, charge doping preserves a positive MAE over the investigated range from q = −0.20e to q = +0.20e. Weak hole doping maximizes the MAE, whereas electron doping enhances the Curie temperature to above 200 K by suppressing negative in-plane exchange contributions. These results show that anisotropy and thermal stability in monolayer Fe3SiTe2 can be tuned through distinct microscopic mechanisms, providing a useful route for engineering 2D magnetic materials for spintronic applications.