Thermally quenched metastable phase in the Ising model with competing interactions

Thermal quenching has been employed to discover various metastable materials such as hard steels and metallic glasses. More recently, quenching-based phase control has been applied to correlated electron systems that exhibit metal-insulator, magnetic, or superconducting transitions. Despite the discovery of metastable electronic phases, however, the microscopic origin of metastability remains elusive, as the system's degrees of freedom—such as electrons—can vary even at low temperatures. Here, using Monte Carlo simulations, we demonstrate a thermally quenched metastable phase in the Ising model that does not conserve the total magnetization. When multiple types of interactions that stabilize different long-range orders are introduced, the ordering kinetics exhibits significant slowing down, and the characteristic timescale for ordering diverges as the temperature decreases. As a result, the system can reach low temperatures without undergoing ordering if the cooling rate is sufficiently high. Quantitative analysis of the divergent behavior suggests that the energy barrier for eliminating the local structure of competing orders is the origin of this metastability. Thus, the present simulation demonstrates that competing interactions play an essential role in achieving metastability.