Ma Li-Ying, Tang Lin, Guan Ze-Lei, He Ke, An Kang, Ma Xu-Cun, Jia Jin-Feng, Xue Qi-Kun, Han Y, Huang Steve, Liu Feng
Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
Phys Rev Lett. 2006 Dec 31;97(26):266102. doi: 10.1103/PhysRevLett.97.266102. Epub 2006 Dec 27.
Using scanning tunneling microscopy, we demonstrate that the nucleation density of Fe islands on the surface of nanoscale Pb films oscillates with the film thickness, providing a direct manifestation of the quantum size effect on surface diffusion. The Fe adatom diffusion barriers were derived to be 204+/-5 and 187+/-5 meV on a 21 and 26 monolayer (ML) Pb film, respectively, by matching the kinetic Monte Carlo simulations to the experimental island densities. The effect is further illustrated by the growth of Fe islands on wedged Pb films, where the Fe island density is consistently higher on the odd-layer films than on the even-layer films in the thickness range of 11 to 15 ML.
利用扫描隧道显微镜，我们证明了纳米级铅膜表面铁岛的成核密度随膜厚度振荡，这是量子尺寸效应在表面扩散上的直接体现。通过将动力学蒙特卡罗模拟与实验岛密度相匹配，得出在21和26单层（ML）的铅膜上，铁吸附原子的扩散势垒分别为204±5和187±5毫电子伏特。在楔形铅膜上铁岛的生长进一步说明了这种效应，在11至15 ML的厚度范围内，奇数层膜上的铁岛密度始终高于偶数层膜。
