Kelleher Colm P, Guerra Rodrigo E, Hollingsworth Andrew D, Chaikin Paul M
Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, New York 10003, USA.
Phys Rev E. 2017 Feb;95(2-1):022602. doi: 10.1103/PhysRevE.95.022602. Epub 2017 Feb 7.
We study the phase behavior of a system of charged colloidal particles that are electrostatically bound to an almost flat interface between two fluids. We show that, despite the fact that our experimental system consists of only 10^{3}-10^{4} particles, the phase behavior is consistent with the theory of melting due to Kosterlitz, Thouless, Halperin, Nelson, and Young. Using spatial and temporal correlations of the bond-orientational order parameter, we classify our samples into solid, isotropic fluid, and hexatic phases. We demonstrate that the topological defect structure we observe in each phase corresponds to the predictions of Kosterlitz-Thouless-Halperin-Nelson-Young theory. By measuring the dynamic Lindemann parameter γ_{L}(τ) and the non-Gaussian parameter α_{2}(τ) of the displacements of the particles relative to their neighbors, we show that each of the phases displays distinctive dynamical behavior.
我们研究了带电胶体粒子系统的相行为，这些粒子通过静电作用与两种流体之间几乎平坦的界面相结合。我们表明，尽管我们的实验系统仅由10³ - 10⁴个粒子组成，但其相行为与由科斯特利茨、索利斯、哈珀林、尼尔森和杨提出的熔化理论相一致。利用键取向序参量的空间和时间相关性，我们将我们的样品分类为固相、各向同性流体相和六方相。我们证明，我们在每个相中观察到的拓扑缺陷结构与科斯特利茨 - 索利斯 - 哈珀林 - 尼尔森 - 杨理论的预测相符。通过测量粒子相对于其相邻粒子位移的动态林德曼参数γₗ(τ)和非高斯参数α₂(τ)，我们表明每个相都表现出独特的动力学行为。
