发表机构
Institute for Solid State Physics, The University of Tokyo; Department of Advanced Materials Science, The University of Tokyo（东京大学固体离子体研究所; 东京大学先进材料科学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过密度泛函理论和区域化学势分析，研究了金刚石(001)表面硅原子的吸附行为，揭示了硅链的一维生长机制及高覆盖率下条纹和正方晶格结构的形成，并表明RCP分析是指导表面结构探索的有效工具。
AI 中文摘要
利用密度泛函理论和区域化学势（RCP）分析，研究了重构金刚石(001)表面上碳二聚体和硅原子的吸附。我们首先证明，RCP分布提供了对键重排的实空间描述，这些键重排导致了实验观察到的碳二聚体带的位点选择性生长。然后，我们考察了单个和多个硅原子的吸附。计算得到的吸附能表明，单个硅原子优先桥接表面碳二聚体，随后吸附的硅原子通过Si-Si键形成而倾向于相邻的二聚体位点。RCP分析识别出有限硅链末端的给电子区域，为其优先一维生长提供了直观解释，并为选择候选吸附结构提供了物理动机明确的策略。在较高的硅覆盖率下，几何优化在金刚石表面产生了硅条纹和平面正方晶格结构。表面相分析表明，有效硅化学势的增加有利于具有逐渐更高硅覆盖率的相，从硅条纹相到硅正方晶格相。计算得到的能带结构显示，随着硅覆盖率的增加，表面带隙逐渐减小。在硅正方晶格结构中，多个能带穿过费米能级，且沿两个面内方向的导电态具有不同的Si和C特征，因为底层金刚石(001)衬底缺乏四重旋转对称性。这些结果确立了RCP分析作为解释表面共价键合和指导探索吸附驱动表面结构的有用方法。
英文摘要
Adsorption of carbon dimers and Si atoms on the reconstructed diamond (001) surface is inves- tigated using density functional theory and regional chemical potential (RCP) analysis. We first demonstrate that the RCP distribution provides a real-space description of the bonding rearrange- ments responsible for the site-selective growth of experimentally observed carbon-dimer ribbons. We then examine the adsorption of single and multiple Si atoms. The calculated adsorption ener- gies show that a single Si atom preferentially bridges a surface carbon dimer and that subsequently adsorbed Si atoms favor neighboring dimer sites through Si-Si bond formation. The RCP analysis identifies electron-donating regions at the ends of finite Si chains, providing an intuitive explanation for their preferential one-dimensional growth and a physically motivated strategy for selecting candi- date adsorption structures. At higher Si coverages, geometry optimizations yield Si stripe and planar square-lattice structures on the diamond surface. Surface phase analysis indicates that an increase in the effective Si chemical potential favors structures with progressively higher Si coverages, from the Si stripe phase to the Si square-lattice phase. The calculated band structures reveal a progressive reduction of the surface band gap with increasing Si coverage. In the Si square-lattice structure, several bands cross the Fermi level, and the conducting states along the two in-plane directions have distinct Si and C character because the underlying diamond (001) substrate lacks fourfold rotational symmetry. These results establish RCP analysis as a useful approach for interpreting surface covalent bonding and guiding the exploration of adsorption-driven surface structures.
Comments13 pages, 14 figures, 3 tables
