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

[Display omitted] •Various critical nuclei are identified by configuration heredity of crystal clusters.•Spinodal limits of supercooled liquids Al are derived from measured nucleation rates.•Homogenous nucleation limit is hardly affected by Stokes-Einstein relation breakdown.•Crystallization under spinodal limit proceeds in continuous and collective mode. 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 τN of supercooled liquids and evaluate the nucleation energy barrier ΔEcri∗ in isothermal crystallization. The estimated kinetic spinodal (i.e., HNL) temperature Tks and thermodynamic spinodal temperature Tts are 0.51 Tm and 0.45 Tm, respectively. At the HNL, the nucleation energy barrier ΔEcri∗ is discovered to be very small, and a critical slowdown behavior is also observed near Tks. A careful analysis for the Stokes-Einstein (SE) relation reveals the temperature TSE of SE relation breakdown is only 0.02 Tm higher than Tks, 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 TSE and Tks can be attributed to a weak glass formation ability of liquid Al.