Martín-Roca José, Martinez Raúl, Martínez-Pedrero Fernando, Ramírez Jorge, Valeriani Chantal
Dep. de Est. de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Dep. Química-Fiśica, Universidad Complutense de Madrid, Avda. Complutense s/n, Madrid 28040, Spain.
J Chem Phys. 2022 Apr 28;156(16):164502. doi: 10.1063/5.0087601.
In this work, we study a two-dimensional system composed by Active Brownian Particles (ABPs) interacting via a repulsive potential with two length scales-a soft shell and a hard core. Depending on the ratio between the strength of the soft shell barrier and the activity, we find two regimes: If this ratio is much larger or smaller than 1, the observed behavior is comparable with ABPs interacting via a single length scale potential. If this ratio is similar to 1, the two length scales are relevant for both structure and dynamical properties. On the structural side, when the system exhibits a motility induced phase separation, the dense phase is characterized by new and more complex structures compared with the hexatic phase observed in single length scale systems. From the dynamic analysis, we find, to our knowledge, the first manifestation of a dynamic heterogeneity in active particles, reminiscent of the glassy dynamics widely studied in passive colloids.
在这项工作中，我们研究了一个二维系统，该系统由通过具有两个长度尺度（软壳和硬核）的排斥势相互作用的活性布朗粒子（ABP）组成。根据软壳势垒强度与活性之间的比率，我们发现了两种情况：如果该比率远大于或小于1，则观察到的行为与通过单一长度尺度势相互作用的ABP相当。如果该比率接近1，则两个长度尺度对结构和动力学性质都有影响。在结构方面，当系统表现出运动诱导的相分离时，与在单一长度尺度系统中观察到的六方相相比，致密相具有新的且更复杂的结构。通过动力学分析，据我们所知，我们发现了活性粒子中动力学非均匀性的首次表现，这让人联想到在被动胶体中广泛研究的玻璃态动力学。
