Bristol Centre for Functional Nanomaterials, University of Bristol, Bristol, BS8 1FD, UK.
H.H. Wills Physics Laboratory, Tyndall Ave., Bristol, BS8 1TL, UK.
Eur Phys J E Soft Matter. 2021 Sep 28;44(9):121. doi: 10.1140/epje/s10189-021-00108-8.
We explore crystallisation and polymorph selection in active Brownian particles with numerical simulation. In agreement with previous work (Wysocki et al. in Europhys Lett 105:48004, 2014), we find that crystallisation is suppressed by activity and occurs at higher densities with increasing Péclet number ([Formula: see text]). While the nucleation rate decreases with increasing activity, the crystal growth rate increases due to the accelerated dynamics in the melt. As a result of this competition, we observe the transition from a nucleation and growth regime at high [Formula: see text] to "spinodal nucleation" at low [Formula: see text]. Unlike the case of passive hard spheres, where preference for FCC over HCP polymorphs is weak, activity causes the annealing of HCP stacking faults, thus strongly favouring the FCC symmetry at high [Formula: see text]. When freezing occurs more slowly, in the nucleation and growth regime, this tendency is much reduced and we see a trend towards the passive case of little preference for either polymorph.
我们通过数值模拟探索了活性布朗粒子中的结晶和多晶型选择。与之前的工作（Wysocki 等人，在《欧洲物理快报》105:48004，2014 年）一致，我们发现结晶受到活性的抑制，并且随着 Peclet 数（[Formula: see text]）的增加，在更高的密度下发生。虽然随着活性的增加，成核速率降低，但由于熔体中动力学的加速，晶体生长速率增加。由于这种竞争，我们观察到从高 [Formula: see text]下的成核和生长转变到低 [Formula: see text]下的“旋节线成核”。与被动硬球的情况不同，其中 FCC 相对于 HCP 多晶型的偏好较弱，活性导致 HCP 堆垛层错的退火，从而在高 [Formula: see text]下强烈有利于 FCC 对称性。当冻结发生得更慢时，即在成核和生长阶段，这种趋势大大减弱，我们看到一种倾向于被动情况，即对两种多晶型几乎没有偏好。
