Supplementary material (clean, not marked-up)

The supplementary marerial include detailed calculations of the Curie temperature Monte Carlo simulation for CrSe2, a diagram showing the selection test for cutoff energy in 2×2 supercells, an ab initio molecular dynamics simulation curve for CrSe2 monolayers at 300 K, band structure, orbital MAE, and PDOS diagrams under different biaxial strains. Additionally, data on energy, MAE, J and magnetic moment of single atoms in CrSe2 monolayers under various biaxial strains are provided.