Jungmann R M, Pereira P C N, Apolinario S W S
Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE, Brazil.
J Phys Condens Matter. 2018 Nov 21;30(46):465402. doi: 10.1088/1361-648X/aae3c5. Epub 2018 Sep 24.
We implement Brownian dynamics to investigate the melting processes of colloidal particles confined isotropically and interacting via a potential which can be tailored in a repulsive-attractive-respulsive fashion as the interparticle distance increases. The stable configurations of such a system is composed of a large diversity of structures, which includes quasicrystalline, triangular, square, and mixed orderings, as well as the presence of fringes and holes, which are located, respectively, at the border and interior of the clusters. Our simulations demonstrate that during the melting process particles are able to swing between different micro phases. This intermediary stage, present in a finite range of temperature, precedes the melting in all cases investigated and is different from the hexatic phase of the KTNHY framework. We also test the fringes stability and find it to be higher than the one found in compact clusters. Finally, we show that, at the high temperature regime, the system loses its angular ordering while still preserves its radial interparticle confinement, which, ultimately, causes the proliferation of small subclusters.
我们采用布朗动力学来研究各向同性受限且通过一种势能相互作用的胶体粒子的熔化过程，该势能可随着粒子间距离增加以排斥 - 吸引 - 排斥的方式进行调整。这样一个系统的稳定构型由多种结构组成，包括准晶、三角形、正方形和混合有序结构，以及条纹和孔洞的存在，它们分别位于团簇的边界和内部。我们的模拟表明，在熔化过程中粒子能够在不同的微相之间摆动。这个中间阶段出现在有限的温度范围内，在所研究的所有情况下都先于熔化，并且不同于KTNHY框架中的六次近晶相。我们还测试了条纹的稳定性，发现其稳定性高于紧密团簇中的稳定性。最后，我们表明，在高温 regime下，系统失去其角向有序性，同时仍保持其粒子间的径向约束，这最终导致小亚团簇的增殖。
