Ouyang Wenze, Zou Shuangyang, Zhong Jun, Xu Shenghua
Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
College of Materials Engineering, North China Institute of Aerospace Engineering, Langfang 065000, China.
Soft Matter. 2023 Aug 23;19(33):6329-6340. doi: 10.1039/d3sm00872j.
By using a large enough number of particles and implementing a parallel algorithm on the CUDA platform, we have performed brute-force molecular dynamics simulations to study the template-induced heterogeneous crystallization in charged colloids. Six kinds of templates, whose patterns include the planes of fcc(100), fcc(110), fcc(111), bcc(100), bcc(110) and bcc(111), have been implanted into the middle of the simulation box. Except the fcc(111) template, whose structure benefits not only fcc but also hcp crystals resulting in a similar behavior to homogeneous crystallization, bcc-type templates favor the formation of bcc crystals and bcc-like precursors while fcc-type templates favor the formation of fcc crystals and fcc-like precursors. Therefore, for fcc(100) and fcc(110) templates, heterogeneous crystallization will definitely result in a fcc crystallite. However, the results of heterogeneous crystallization that are induced by bcc-type templates are subtly different at different state points. At the state points where the interaction strength of charged colloids is weak and the fcc phase is thermodynamically stable, the bcc crystals formed with the promotion of bcc-type templates are not stable so as to tend to transform into fcc or hcp crystals. When the interaction strength of charged colloids is high, the predominant bcc crystals formed with the promotion of bcc-type templates can always persist within the time scale of simulation although not bcc but fcc crystals are thermodynamically stable.
通过使用足够数量的粒子并在CUDA平台上实现并行算法，我们进行了蛮力分子动力学模拟，以研究带电胶体中模板诱导的非均相结晶。六种模板，其图案包括面心立方（100）、面心立方（110）、面心立方（111）、体心立方（100）、体心立方（110）和体心立方（111）平面，已被植入模拟盒中间。除了面心立方（111）模板，其结构不仅有利于面心立方晶体，也有利于六方密堆积晶体，导致与均相结晶类似的行为，体心立方型模板有利于体心立方晶体和类体心立方前驱体的形成，而面心立方型模板有利于面心立方晶体和类面心立方前驱体的形成。因此，对于面心立方（100）和面心立方（110）模板，非均相结晶肯定会产生一个面心立方微晶。然而，体心立方型模板诱导的非均相结晶结果在不同状态点略有不同。在带电胶体相互作用强度较弱且面心立方相热力学稳定的状态点，在体心立方型模板促进下形成的体心立方晶体不稳定，从而倾向于转变为面心立方或六方密堆积晶体。当带电胶体的相互作用强度较高时，在体心立方型模板促进下形成的主要体心立方晶体在模拟时间尺度内总能持续存在，尽管热力学稳定的不是体心立方晶体而是面心立方晶体。
