Mauleon-Amieva Abraham, Mosayebi Majid, Hallett James E, Turci Francesco, Liverpool Tanniemola B, van Duijneveldt Jeroen S, Royall C Patrick
H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom.
Phys Rev E. 2020 Sep;102(3-1):032609. doi: 10.1103/PhysRevE.102.032609.
Swimmers and self-propelled particles are physical models for the collective behavior and motility of a wide variety of living systems, such as bacteria colonies, bird flocks, and fish schools. Such artificial active materials are amenable to physical models which reveal the microscopic mechanisms underlying the collective behavior. Here we study colloids in a dc electric field. Our quasi-two-dimensional system of electrically driven particles exhibits a rich and exotic phase behavior exhibiting passive crystallites, motile crystallites, an active gas, and banding. Amongst these are two mesophases, reminiscent of systems with competing interactions. At low field strengths activity suppresses demixing, leading to motile crystallites. Meanwhile, at high field strengths, activity drives partial demixing to traveling bands. We parametrize a particulate simulation model which reproduces the experimentally observed phases.
游泳者和自推进粒子是多种生命系统集体行为和运动性的物理模型，例如细菌菌落、鸟群和鱼群。这类人工活性材料适用于揭示集体行为背后微观机制的物理模型。在此，我们研究直流电场中的胶体。我们的电驱动粒子准二维系统展现出丰富且奇特的相行为，包括被动微晶、能动微晶、活性气体和条带。其中有两个中间相，让人联想到具有竞争相互作用的系统。在低场强下，活性抑制了相分离，导致能动微晶的出现。同时，在高场强下，活性促使部分相分离形成移动条带。我们对一个颗粒模拟模型进行参数化，该模型再现了实验观察到的相。
