Fitting cutoffs ( Å) for n th order of force constants Period number and) shows our cutoff generator leads to converged fitting results. Furthermore, the choice of a second-order cutoff significantly impacts the convergence of RMSE in the context of supercell size. Effective coordination of supercell size and cutoff parameters is essential for achieving RMSE convergence. Using cubic GaAs as an example (Figure ), for a 4 × 4 × 4 supercell (16 Å lattice), the RMSE fluctuates against 27 sets of cutoffs at ∼20 meV/ Å before converging to 10 meV/ Å in 5 × 5 × 5 supercell (20 Å lattice).