Why do some quasicrystals change into ordinary crystal structures at lower temperatures?

Quasicrystals are thermodynamically stable phases that typically exist only within a limited temperature range near their melting point. As temperatures decrease, these materials often transform into ordinary crystal structures.1

The stability of a material is determined by its free energy, which is calculated as the internal energy minus the product of temperature and entropy. While energy accounts for the specific atomic arrangements, entropy represents a measure of fluctuations around an ideal structure. It is likely that entropy must be considered alongside energy to fully explain why quasicrystals are stable at higher temperatures but transition to conventional crystalline forms as the system cools.1

Essentially, the quasicrystalline state is favored under specific thermodynamic conditions where the balance between energy and entropy minimizes the total free energy of the system. Once the temperature drops, the system shifts toward a more stable, periodic crystalline arrangement to achieve a lower free-energy state.1