AI 中文总结
针对多步成核中实验与理论成核速率的差异，本研究开发多壳层模型，通过随机模拟揭示重排速率可改变成核速率数个数量级，耦合强度增加会引发平均首次通过时间与重排 susceptibility 的非单调关系，阐明多步成核机制并提供预测框架。
AI 中文摘要
成核是相变与相分离的关键限速过程。近期研究表明，实验测得的成核速率与理论预测存在显著差异，尤其是在多步路径伴随动态结构重排的情况下。为弥合这一差距，本研究开发了含时空依赖序参量场的多壳层模型，以描述重排成核过程，其中结构重组与凝聚簇的早期生长耦合。通过随机模拟，追踪生长簇内异质结构序的时间分辨演化。对早期成核首次通过问题的路径分析表明，重排速率的变化可使成核速率改变数个数量级。此外，随着耦合强度增加，平均首次通过时间与重排 susceptibility 的关系从单调转变为非单调，呈现出转变效应。本研究用考虑非平衡特性的有效成核势垒定量解释这些行为，研究结果阐明了多步成核的机制，为后续研究提供了预测框架。
英文摘要
Nucleation is a key rate-limiting process in phase transition and phase separation. Recent studies highlight a significant discrepancy between experimentally measured nucleation rates and theoretical predictions, particularly when dynamic structural reordering occurs along multi-step pathways. To bridge this gap, we develop a multi-shell model with a space-time-dependent order-parameter field to describe the reordering-nucleation process, where structural reorganization couples with the early growth of condensed clusters. Through stochastic simulations, we track the time-resolved evolution of heterogeneous structural order inside growing clusters. Path analysis of the first-passage problem in early-stage nucleation demonstrates that shifting the reordering rate alters the nucleation rate by several orders of magnitude. Furthermore, as the coupling strength increases, the relationship between the mean first-passage time and reordering susceptibility shifts from monotonic to non-monotonic, exhibiting a turnover effect. We quantitatively rationalize these behaviors with an effective nucleation barrier that accounts for non-equilibrium properties. Our findings elucidate the mechanisms behind multi-step nucleation and offer a predictive framework for future studies.
