石墨碳高压相变的第一性原理动力学模拟计算研究

项目名称： 石墨碳高压相变的第一性原理动力学模拟计算研究

项目编号： No.11274356

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 王建涛

作者单位： 中国科学院物理研究所

项目金额： 78万元

中文摘要： 碳元素是自然界中分布最为广泛的元素之一。单质碳通常以石墨和金刚石两种晶型存在。碳晶体结构及其相变的研究是理解其物性和应用的基础。但是长期以来关于层状石墨碳的高温高压相变机制一直困扰着实验和理论科学工作者。最近通过对石墨冷压相变的研究使得这一工作取得显著进展。我们通过第一性原理模拟计算研究了石墨碳的冷压相变机制并发现了两个新的三维正交碳亚稳相W-carbon和O-carbon。为了全面地理解从层状石墨到金刚石的高压相变机理，本研究拟通过第一性原理动力学模拟计算，从热力学和动力学两方面系统地研究石墨碳的高压相变机制及其形成的三维碳晶体结构的结构稳定性及相关物性。重点探讨（1）冷压石墨高压亚稳相的晶体结构及其相变过程；（2）高压下由石墨形成立方晶碳结构的动力学机制；（3）高温高压下从石墨亚稳相到金刚石的相变机制。

中文关键词： 金刚石结构；碳烯结构；高压相变；第一性原理计算；

英文摘要： Phase transformation of graphite is among the most intriguing topics in materials science. Beside the high-pressure and high-temperature phase transformation to form diamond, the crystal structures of graphite compressed at room temperature and the corresponding structural transformation mechanism have been longstanding. The phase transformation process is highly complicated and remains poorly understood despite extensive past effort. Compressed graphite acts as a key gateway toward various diamond phases; an accurate mapping of its structural landscape is essential to understanding the intricate phase relations among various carbon allotropes. Experimentally, an unquenchable transparent and hard phase that has long been observed during the cold-compression (at room temperature) stage of the synthesis. Recent studies identified several structural forms for cold-compressed graphite, including a monoclinic M-carbon and an orthorhombic W-carbon, which provide a critical link for the graphite-to-diamond transformation. However, graphite's layered structure is conducive to the sliding and buckling of the graphitic sheets during the initial stages of compression, which introduces a high degree of complexity in the structural landscape of compressed graphite. In present work, we perform by ab initio calculations a d

英文关键词： Diamond；Carbene；Morphed Graphene；Ab initio calculations；