Determination of preferential rare earth adatom adsorption geometries on Si(001)

The adsorption patterns of rare earth atoms on Si(001) were investigated using scanning tunneling microscopy measurements and density functional calculations. Stable configurations were systematically determined via calculation of binding energies of various adatom coverage and adsorption geometry. Competition between inter-adatom hybridization and Coulomb repulsion is the mechanism contributing to binding energy minima associated with commonly observed rare earth adsorption geometries. Comparison of stable configurations with experimental scanning tunneling microscopy images demonstrated accuracy of the theoretical models. This paves a way for the understanding of self-assembly of rare earth disilicide nanowires on vicinal Si(001) substrates.

利用扫描隧道显微镜测量和密度泛函计算研究了稀土原子在Si(001)表面的吸附模式。通过计算不同吸附原子覆盖度和吸附几何结构的结合能，系统地确定了稳定构型。吸附原子间杂化和库仑排斥之间的竞争是导致与常见稀土吸附几何结构相关的结合能极小值的机制。稳定构型与实验扫描隧道显微镜图像的比较证明了理论模型的准确性。这为理解稀土二硅化物纳米线在相邻Si(001)衬底上的自组装铺平了道路。