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arXiv 1401.0696cond-mat.stat-mechcond-mat.soft
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模拟胶体悬浮液中沉积物的初始生长

Simulating the initial growth of a deposit from colloidal suspensions

T. J. Oliveira, F. D. A. Aarao Reis

摘要:

本文研究了一个二维薄膜生长模型的短时性质,在该模型中入射粒子作对流扩散运动,先作垂直步,后作$D$水平步。该模型反映了物理评论快报实验中各向异性胶体颗粒沉积的一些特征。{ \bf 110},035501(2013),其中漂移颗粒被吸引到沉积物中的颗粒富集区域。随着$D$从$0$(弹道沉积)增加到$8$,观察到从粗糙结构到柱状结构的高度轮廓变化,与实验结果惊人的相似。有效的增长指数匹配的实验估计和缩放的$D$上的这些指数的颗粒沉积物相互作用的范围显示出显着的效果。胶体颗粒的近椭圆形的形状表示为平行的实验的条件下,粗糙度指数的计算,给出了一个范围内的估计,也包括实验值。从自相关函数计算出的有效动态指数被证明是合适的,以决定一个真正的动态缩放或瞬态行为之间,特别是因为后者导致的指数关系的偏差。这些结果与Phys. Rev. Lett { \bf 111},209601(2013)关于短时间不稳定(柱状)生长的论点一致,表明临界淬灭KPZ动力学不能解释胶体颗粒沉积问题。

英文摘要:

We study the short time properties of a two-dimensional film growth model in which incident particles execute advective-diffusive motion with a vertical step followed by $D$ horizontal steps. The model represents some features of the deposition of anisotropic colloidal particles of the experiment in Phys. Rev. Lett. {\bf 110}, 035501 (2013), in which wandering particles are attracted to particle-rich regions in the deposit. Height profiles changing from rough to columnar structure are observed as $D$ increases from $0$ (ballistic deposition) to $8$, with striking similarity to the experimental ones. The effective growth exponents matches the experimental estimates and the scaling of those exponents on $D$ show a remarkable effect of the range of the particle-deposit interaction. The nearly ellipsoidal shape of colloidal particles is represented for the calculation of roughness exponents in conditions that parallel the experimental ones, giving a range of estimates that also include the experimental values. The effective dynamic exponents calculated from the autocorrelation function are shown to be suitable to decide between a true dynamic scaling or transient behavior, particularly because the latter leads to deviations in an exponent relation. These results are consistent with arguments on short time unstable (columnar) growth of Phys. Rev. Lett {\bf 111}, 209601 (2013), indicating that critical quenched KPZ dynamics does not explain that colloidal particle deposition problem.

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