Fichthorn KA, Scheffler M
Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Phys Rev Lett. 2000 Jun 5;84(23):5371-4. doi: 10.1103/PhysRevLett.84.5371.
We describe a theoretical study of the role of adsorbate interactions in island nucleation and growth, using Ag/Pt(111) heteroepitaxy as an example. From density-functional theory, we obtain the substrate-mediated Ag adatom pair interaction and we find that, past the short range, a repulsive ring is formed about the adatoms. The magnitude of the repulsion is comparable to the diffusion barrier. In kinetic Monte Carlo simulations, we find that the repulsive interactions lead to island densities over an order of magnitude larger than those predicted by nucleation theory and thus identify a severe limitation of its applicability.
我们以Ag/Pt(111)异质外延为例，描述了吸附质相互作用在岛状核形成与生长中作用的理论研究。从密度泛函理论出发，我们得到了衬底介导的银吸附原子对相互作用，并发现，在短程作用之后，吸附原子周围会形成一个排斥环。排斥力的大小与扩散势垒相当。在动力学蒙特卡洛模拟中，我们发现排斥相互作用导致岛密度比成核理论预测的大一个数量级以上，从而确定了其适用性的一个严重限制。
