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使用密度泛函方法对C原子在Fe(111)表面吸附团聚和次表层的吸附扩散进行了研究。在炭覆盖度θC<1 ML时,C主要以孤立的原子态存在并导致表面重构;1 ML≤θC≤2 ML,“mC2+nC”为主要的吸附形式;θc≥2 ML时,复杂的吸附形态比如碳链和岛状碳团簇开始生成。这些复杂岛状碳团簇是Fe(111)表面石墨沉积或碳纳米管生长的成核中心。在次表层,C原子在八面体位稳定存在。C在表面的迁移能垒为0.45 eV,由表面迁移到次表面的的能垒为0.73 eV。虽然C2团簇的生成是热力学有利的,但是C向次表层的迁移动力学上占优。
Density functional theory was used to study the adsorption and aggregation of C atom on Fe (111) surface and the adsorption and diffusion of subsurface. When the carbon coverage θC <1 ML, C exists mainly in isolated atomic states and leads to surface reconstruction; 1 ML≤θC≤2 ML, “mC2 + nC” is the main adsorption form; when θc≥2 ML , Complex adsorption morphology such as carbon chains and island carbon clusters begin to form. These complex island carbon clusters are the nucleation centers for Fe (111) surface graphite deposition or carbon nanotube growth. In the subsurface, C atoms are stable in the octahedral position. The migration barrier of C at the surface is 0.45 eV, and the energy barrier of migration from the surface to the sub-surface is 0.73 eV. Although the formation of C2 clusters is thermodynamically favorable, the migration kinetics of C to the subsurface is dominant.