PbTiO3薄膜生长的Monte Carlo模拟Ⅰ：模型与算法

Simulation of the growth of PbTiO3 thin film by Monte Carlo method Ⅰ:model and algorithm

提出了一种基于Monte Carlo方法的模拟多元氧化物薄膜生长的三维模型及模拟算法,并以模拟PbTiO3薄膜的生长为例加以说明.模拟中使用的晶格空间基本单元为立方体,单个的ABO3结构晶胞简化为2×2×2个立方体,并采用周期性边界条件;Monte Carlo事件由沉积事件,扩散事件和脱附事件组成;根据PbTiO3的组成确定沉积原子的种类和比例,即根据Pb∶Ti∶O为1∶1∶3的比例借助一随机数随机选择原子的种类;原子扩散能力与扩散激活能相关,单个原子的扩散步数由沉积速率与实际扩散时间决定;激活能采用库仑势计算,其大小不仅与原子周围的架构相关,而且与架构中原子的种类相关.有关模拟结果将在另文中给出.

Based on Monte Carlo （MC） method and taken PbTiO3 （abbreviated as PTO） thin film as an example, a three-dimensional model and a related algorithm for the simulation of the growth of multi-element oxide thin films were presented in this paper. The basic unit of the MC lattice was cubic, a single ABO3 crystal unit is modeled as a 2×2× 2 cubic, and the periodic condition was used. The MC events consist of deposition, diffusion and re-evaporation events. The kind of atoms being deposited was chosen randomly according to the ratio of Pb ： Ti ： O= 1 ： 1 ： 3 by a stochastic number. The active energy of different atoms was not only related to the local configuration, but related to the kind of the atoms of the configuration as well. The active energy was considered from the interactions between the ions, which are calculated by Coulombic potential function. The simulation results will be discussed in authers＇ another paper.