摘要
The lattice constants of diamond and graphite at high pressure and high temperature (HPHT) were calculated on the basis of linear expansion coefficient and elastic constant. According to the empirical electron theory of solids and molecules (EET), the valence electron structures (VESs) of diamond, graphite crystal and their common planes were calculated. The relationship between diamond and graphite structure was analyzed based on the boundary condition of the improved Thomas-Fermi-Dirac theory by Cheng (TFDC). It was found that the electron densities of common planes in graphite were not continuous with those of planes in diamond at the first order of approximation. The results show that during the course of diamond single crystal growth at HPHT with metal catalyst, the carbon sources forming diamond structure do not come from the graphite structure directly. The diamond growth mechanism was discussed from the viewpoint of valence electron structure.
The lattice constants of diamond and graphite at high pressure and high temperature （HPHT） were calculated on the basis of linear expansion coefficient and elastic constant. According to the empirical electron theory of solids and molecules （EET）, the valence electron structures （VESs） of diamond, graphite crystal and their common planes were calculated. The relationship between diamond and graphite structure was analyzed based on the boundary condition of the improved Thomas-Fermi-Dirac theory by Cheng （TFDC）. It was found that the electron densities of common planes in graphite were not continuous with those of planes in diamond at the first order of approximation. The results show that during the course of diamond single crystal growth at HPHT with metal catalyst, the carbon sources forming diamond structure do not come from the graphite structure directly. The diamond growth mechanism was discussed from the viewpoint of valence electron structure.
作者
LI Li1,2, XU Bin2,3 & LI MuSen1,2 1 School of Materials Science & Engineering, Shandong University, Jinan 250061, China
2 Shandong Engineering Research Center for Super Hard Materials, Zoucheng 273500, China
3 School of Materials Science & Engineering, Shandong Jianzhu University, Jinan 250101, China
基金
the National Natural Science Foundation of China (Grant Nos. 50371048 and 50372035)
the Natural Science Foundation of Shandong Province of China (Grant No. Y2007F11)
关键词
钻石
晶体生长
石墨
碳源
价电子结构
diamond crystal, graphite, carbon source, valence electron structure
