Dynamical mechanism for the formation of metastable phases

Rapid temperature quenches have long been known to produce metastable thermodynamic phases. We study Landau-Ginzburg models of phase transitions for free energies having three local minima and show that metastable phases can be formed via a dynamic instability that splits the front separating the stable high- and low-temperature phases. Even though quenching may nucleate the stable phase, the splitting instability we discuss will favor the formation of the metastable phase.