Cavalcanti W, Santos M, Figueiredo W
Departamento de Física, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, SC, Brazil.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Feb;69(2 Pt 1):021608. doi: 10.1103/PhysRevE.69.021608. Epub 2004 Feb 27.
The aim of this work is to present a simple model for studying the texture formation during the electrodeposition process. Monte Carlo simulations are used to describe the formation of the deposits, and the scaling concepts are employed to characterize their growth and roughness properties. In this model particles are randomly deposited with an orientation chosen from a discrete set of possible directions. The final orientation of the deposited particle is determined by its interaction with the first neighboring particles and by the temperature of the substrate. Particle interactions are chosen according to the q-state ferromagnetic Potts model Hamiltonian. Simulations were performed on (1+1) dimensions, and for several values of temperature and substrate size. The results of the simulations lead to different behaviors for the model at low and high temperatures. At high temperatures, the scaling exponent beta=0.5 was found, which characterizes a pure random deposition model. However, at low temperatures, we observed that after a given time interval, particles start orienting in a fixed direction and the interface width saturates just during a time window. Suddenly, a fluctuation makes the interface width increase again, that is, we never observed a full saturation. On the other hand, at zero temperature, the system reaches an absorbing state with all the layers occupied by particles oriented in the same direction. At zero temperature we found z=1.90, alpha=1.80, and beta=0.99 for the dynamic, roughness, and growth exponents, respectively. The scaling exponents are consistent with a self-affine behavior of the model and they are in agreement with the well known Family-Vicsek scaling relation.
这项工作的目的是提出一个简单模型,用于研究电沉积过程中的纹理形成。采用蒙特卡罗模拟来描述沉积物的形成,并运用标度概念来表征其生长和粗糙度特性。在该模型中,粒子以从一组离散的可能方向中选择的取向随机沉积。沉积粒子的最终取向由其与第一个相邻粒子的相互作用以及基底温度决定。粒子间相互作用根据q态铁磁Potts模型哈密顿量来选择。在(1 + 1)维上进行模拟,并针对几个温度值和基底尺寸进行模拟。模拟结果导致该模型在低温和高温下呈现不同行为。在高温下,发现标度指数β = 0.5,这表征了一个纯随机沉积模型。然而,在低温下,我们观察到在给定的时间间隔后,粒子开始沿固定方向取向,并且界面宽度仅在一个时间窗口内达到饱和。突然,一次涨落使界面宽度再次增加,也就是说,我们从未观察到完全饱和。另一方面,在零温度下,系统达到一个吸收态,所有层都被沿相同方向取向的粒子占据。在零温度下,我们分别发现动力学、粗糙度和生长指数z = 1.90、α = 1.80和β = 0.99。这些标度指数与该模型的自仿射行为一致,并且与著名的Family - Vicsek标度关系相符。