FIG. . Schematic of phase stability as a function of temperature following Aykol et al. Two phases are thermodynamically stable below the melting point, Tm, at low and high temperature, respectively. Furthermore, two phases that are never thermodynamically stable are indicated; one of these can be metastable, whereas the other is unstable at all conditions, since it is of higher energy than an amorphous phase. The amorphous phase is depicted as a continuation of the liquid phase, although small deviations are expected due to differences in the structure of a liquid and an amorphous solid.