to provide a better prediction of 520 K even though it is a lower level of theory. Here too at work is the high sensitivity of phase transition temperature to small variations in energy. The free energy difference between the two phases is marginal, at less than 4 meV/atom from 300 K to 600 K. A tiny uncertainty in the computed energy values of ground state DFT energy or harmonic/anharmonic contribution to vibrational energy would disproportionately swing the critical temperature prediction. It should be highlighted that spontaneous anisotropy is a common feature in cubic IV-VI materials like GeTe , which could account for the observed shallow energy differences. Enhancing the prediction accuracy for GeTe would require more precise techniques for calculating both the vibrational free energy and the ground state total energy.