Fig. 2: Phase transition kinetics.

In situ POM showing the I-II (a) and II-III (b). Intensity changes of the crystals observed under in situ POM (c), we observe the avalanche behavior of the I-II transition (d) and see the stark difference in kinetics (e) between the I-II and II-III heating transitions. The dark blue and red lines indicate the I-II and II-III transitions, respectively, and the yellow and blue arrows indicate the heating and cooling transitions respectively. Black arrows indicate the axis for each line. Schematic showing the typical modes for initiation and propagation of the I-II (f) and II-III (g) transition.