香港科技大学韩一龙、李波等在最新研究中提出了晶体表面的多态晶体润湿层。该研究于2023年2月13日发表于国际一流学术期刊《自然—物理学》杂志上。

与表面预熔类似，研究人员表明晶体表面可以经历预固-固转变。这意味着如果两个晶体能形成低能相干界面，在达到固-固转变温度之前就会形成薄的多态晶体层。该团队在单粒子分辨率的模拟和胶体实验中证实了这一点。表层厚度的幂律增长与预熔相似。在不同的体系中观察到不同的表面晶体生长动力学和可逆性。表面晶体不仅在热平衡状态下存在，而且在熔化、结晶和晶粒粗化过程中也存在。

此外，预熔和预固-固转变可以共存，从而形成双重表面润湿层。研究人员假设这种表面现象也存在于一些原子和分子晶体中，这可能提供了一种调节材料性质的机制。

附：英文原文

Title: Polymorphic crystalline wetting layers on crystal surfaces

Author: Wang, Xipeng, Li, Bo, Li, Mengmeng, Han, Yilong

Issue&Volume: 2023-02-13

Abstract: Analogous to surface premelting, we show that a crystal surface can undergo a pre-solid–solid transition. This means that it develops a thin polymorphic crystalline layer before reaching the solid–solid transition temperature if two crystals can form a low-energy coherent interface. We confirm this in simulations and colloid experiments at single-particle resolution. The power-law increase of surface layer thickness is analogous to premelting. Different kinetics and reversibilities of surface-crystal growth are observed in various systems. Surface crystals exist not only under thermal equilibrium but also during melting, crystallization and grain coarsening. Furthermore, the premelting and pre-solid–solid transition can coexist, resulting in double surface wetting layers. We hypothesize that such surface phenomena also exist in some atomic and molecular crystals, and this could provide a mechanism to tune the properties of the materials.

DOI: 10.1038/s41567-022-01923-2

Source: https://www.nature.com/articles/s41567-022-01923-2