石墨烯形核初期Cu(111)面上CxHy团簇生成的理论研究

采用基于密度泛函理论的第一原理计算方法，我们研究了Cu(111)表面上石墨烯成核生长过程中CxHy小团簇的吸附和生成行为. 计算结果表明：随着氢原子饱和度、氢原子个数的增大，CxHy团簇的形成能减小，碳原子与铜表面的平均距离增加，C-C键的平均键长呈增大趋势. 然而，当生成的CxHy团簇具有空间对称结构时，在一定程度上打破了上述规律性. 令人惊奇的是，形成的C3H4和C3H5对称团簇具有类似石墨烯的空间结构，这类结构可能在石墨烯的形成过程中起着重要的作用.

Theoretical study of the formation of CxHy clusters on Cu(111) surface in the initial stage of grapheme growth

Using first-principles calculations within density function theory, we have investigated the adsorption and formation behaviors of CxHy small clusters during graphene nucleation and growth on a Cu(111) surface. Our calculations show that, with the increase of the value of hydrogen saturation and the number of hydrogen atoms, the formation energy per atom of CxHy clusters decreases, the average distance between carbon atom and the copper surface increases, and the average length of C-C bond also shows a trend of increase. Nevertheless, when the generated CxHy clusters with spatial symmetrical structure, the above rules are broken to some extent. Amazingly, the formed C3H4 and C3H5 symmetric clusters possess graphene-like spatial structure, these kind of structure may be plays an important role in the synthesis of graphene.