Spinodal limits of supercooled liquid Al deduced from configuration heredity of crystal clusters

Whether one-component supercooled liquid encounters a spinodal limit at a sufficiently low temperature has been a controversial issue. To explore the homogeneous nucleation limit (HNL) in liquid Al, a series of molecular dynamics simulations have been performed, and a unique technique able to distinguish the critical nucleus from various embryos has been adopted to measure the crystal nucleation time τ_N of supercooled liquids and evaluate the nucleation energy barrier ΔE_cri^∗ in isothermal crystallization. The estimated kinetic spinodal (i.e., HNL) temperature T_ks and thermodynamic spinodal temperature T_ts are 0.51 T_m and 0.45 T_m, respectively. At the HNL, the nucleation energy barrier ΔE_cri^∗ is discovered to be very small, and a critical slowdown behavior is also observed near T_ks. A careful analysis for the Stokes-Einstein (SE) relation reveals the temperature T_SE of SE relation breakdown is only 0.02 T_m higher than T_ks, and the occurrence of HNL is not affected by whether the SE relation breaks down or not. These results are consistent with previous reports. To some extent, the small gap between T_SE and T_ks can be attributed to a weak glass formation ability of liquid Al.