To compute the harmonic phonon dispersion, we computed harmonic force constants within a 2 × 2 × 2 supercell using the finite-difference method implemented in PHONOPY . For the DFT-based force calculations, the plane-wave energy cutoff was set to 400 eV, which is the value used for the MLFF training. Good agreement is observed between DFT and MLFF for energies, forces, MSD, and harmonic phonons. The MLFF has near-DFT accuracy, which gives us confidence in the results presented in this study.