Bommineni Praveen K, Klement Marco, Engel Michael
Institute for Multiscale Simulation, IZNF, Friedrich-Alexander University Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany.
Phys Rev Lett. 2020 May 29;124(21):218003. doi: 10.1103/PhysRevLett.124.218003.
Computer simulations of the fluid-to-solid phase transition in the hard sphere system were instrumental for our understanding of crystallization processes. But while colloid experiments and theory have been predicting the stability of several binary hard sphere crystals for many years, simulations were not successful to confirm this phenomenon. Here, we report the growth of binary hard sphere crystals isostructural to Laves phases, AlB_{2}, and NaZn_{13} in simulation directly from the fluid. We analyze particle kinetics during Laves phase growth using event-driven molecular dynamics simulations with and without swap moves that speed up diffusion. The crystallization process transitions from nucleation and growth to spinodal decomposition already deep within the fluid-solid coexistence regime. Finally, we present packing fraction-size ratio state diagrams in the vicinity of the stability regions of three binary crystals.
硬球系统中流体到固体相变的计算机模拟对我们理解结晶过程起到了重要作用。然而，尽管胶体实验和理论多年来一直在预测几种二元硬球晶体的稳定性，但模拟未能成功证实这一现象。在此，我们报告在模拟中直接从流体中生长出与Laves相、AlB₂和NaZn₁₃同构的二元硬球晶体。我们使用带有和不带有加速扩散的交换移动的事件驱动分子动力学模拟来分析Laves相生长过程中的粒子动力学。结晶过程在流体 - 固体共存区域深处就从成核和生长转变为旋节线分解。最后，我们给出了三种二元晶体稳定性区域附近的堆积分数 - 尺寸比状态图。
