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利用线膨胀系数和弹性常数计算了金刚石和石墨在高温高压下的晶格常数,根据固体与分子经验电子理论(EET)计算了金刚石、石墨以及它们主要晶面的价电子结构.以程氏理论(TFDC)提出的原子界面边界条件为判据,分析了金刚石和石墨主要晶面之间电子密度的连续性,发现其在一级近似条件下均不连续,不满足金刚石晶体生长的边界条件.分析得知,在高温高压触媒法合成金刚石单晶生长过程中,所需的碳源并非直接来自石墨,从电子结构角度对金刚石单晶的生长机制进行了探讨.
The lattice constants of diamond and graphite under high temperature and high pressure were calculated by using the linear expansion coefficient and the elastic constant. The valence electron structures of diamond, graphite and their main crystal planes were calculated according to the solid and molecule empirical electron theory (EET) (TFDC) as the criterion, the continuity of electron density between diamond and graphite main planes was analyzed and found to be discontinuous under the first-order approximation, which did not meet the boundary conditions of diamond crystal growth. The analysis shows that during the growth process of diamond single crystals synthesized by high temperature and high pressure catalyst method, the required carbon source is not directly from graphite, and the growth mechanism of diamond single crystal is discussed from the electronic structure.