分子动力学模拟石墨烯材料缺陷演化机理

摘要石墨烯因为其存在很多优良性质而成为研究热点，引入缺陷或掺杂其他原子可以有效改善石墨烯的电磁学性能。Di-vacancy（V2）是石墨烯中的一种结构缺陷，比较常见的有 V2(5-8-5),V2(555-777),V2(55-77),V2(5555-6-7777)。这四种缺陷可以在一定情况下相互转化。本文采用分子动力学方法模拟研究这四种缺陷在受到高能脉冲以及应力作用时的结构演化，从微结构演化过程中关键原子能量变化角度为缺陷转化过程提供了物理解释：缺陷吸收足够的能量突破能垒从一种相对稳定结构转变到另一种相对稳定结构。引入概率分析的方法，分析了四种 V2 缺陷转化的概率随脉冲给予能量变化的关系，并发现 V2（55-77）的转化率明显要高于其他三种缺陷，说明 V2（55-77）是四种缺陷中最不稳定的。 68690

毕业论文关键词石墨烯缺陷演化高能脉冲应力分子动力学模拟

毕业设计说明书外文摘要

Title Molecular dynamics simulation of evolution mechanism of pacancy in graphene

Abstract

Graphene has been attracting much attention because it has many fascinating properties. The introduction of defects or doping other atoms can effectively improve the electromagnetic properties of graphene. Divacancy(V2), one type of intrinsic defects in graphene, has four types -- V2(5-8-5), V2(555-777), V2(55-77), V2(5555-6-7777). One of the four defects can be transformed to another on certain conditions. This thesis focuses on transformation of different pacancy structure in suspended graphene induced by high-energy pulse or stress via molecular dynamics (MD) simulation. Physical explanation is drawn from changes in energy of corresponding atoms: defects absorb enough energy, break through energy barrier and then are transformed from one relatively stable forms into another relatively stable forms. Probability analysis is also utilized to analyze the relationship between probability of transformation and energy pulse. V2(55-77) is found to be the most unstable type of pacancy because the transformation probability of V2(55-77) is apparently higher than that of the other three types of pacancy.

Keywords graphene evolution of pacancy high-energy pulse stress molecular dynamics simulation

本科毕业设计说明书第 I 页

1 绪论 1

1.1 石墨烯简介 1

1.2 关于石墨烯的结构缺陷 2

1.3 前人工作总结 3

1.4 本文研究内容 4

2 分子动力学 5

2.1 分子动力学简介 5

2.2 分子动力学常用软件及 LAMMPS 简介 5

2.3 本文所用方法和一些细节 5

3 高能脉冲下 V2 缺陷间的相互转化 8

3.1 研究方法 8

3.2 AIREBO 势计算结果 12

3.3 ReaxFF 势计算结果 18

3.4 分析与总结 24

4 高能脉冲下 V2 缺陷转化的概率统计分析 26

4.1 研究方法 26

4.2 结果 26

4.3 分析与总结 29

5 应力加载下 V2 缺陷间的相互转化 3 0 分子动力学模拟石墨烯材料缺陷演化机理:http://www.751com.cn/wuli/lunwen_77299.html