Computational Materials Science Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan.
Sci Rep. 2011;1:162. doi: 10.1038/srep00162. Epub 2011 Nov 21.
Nucleation, commonly associated with discontinuous transformations between metastable and stable phases, is crucial in fields as diverse as atmospheric science and nanoscale electronics. Traditionally, it is considered a microscopic process (at most nano-meter), implying the formation of a microscopic nucleus of the stable phase. Here we show for the first time, that considering long-range interactions mediated by elastic distortions, nucleation can be a macroscopic process, with the size of the critical nucleus proportional to the total system size. This provides a new concept of "macroscopic barrier-crossing nucleation". We demonstrate the effect in molecular dynamics simulations of a model spin-crossover system with two molecular states of different sizes, causing elastic distortions.
成核，通常与亚稳相与稳定相之间的不连续转变有关，在大气科学和纳米电子学等领域都至关重要。传统上，它被认为是一个微观过程（最多纳米级），意味着稳定相的微观核的形成。在这里，我们首次表明，考虑到由弹性变形介导的远程相互作用，成核可以是一个宏观过程，临界核的大小与整个系统的大小成正比。这提供了一个新的“宏观势垒穿越成核”的概念。我们在具有不同大小的两种分子态的模型自旋交叉体系的分子动力学模拟中证明了这种效应，这会导致弹性变形。
