理论预测晶体表面吸附二维原子岛的形状

Theoretical prediction of the shape of two-dimensional adatom islands on crystal surface

提出了凝结势概念用以建立一种预测晶体表面吸附二维原子岛几何结构的理论方法.基于半经验相互作用势(SEAM势和OJ势)的计算表明,同相外延生长的二维原子岛在Cu和Ag的(111)面呈现正六边形结构,而在Pt(111)面呈现截角三角形状;Cu和Ag的(100)面二维岛则形成正方形.这些理论预测均与实验观测结果一致.由于凝结势的计算不受原子数量的限制,该模型可普遍应用于预测各种表面二维原子岛形状.

By introducing a concept of condensing potential, a theoretical method is established to predict the geometric structure of two-dimensional （2D） adatom islands on crystal surface. Calculations based on semi-empirical potentials （surface-embedded- atom method potential and O. Johnson potential） show that on Cu（ 111 ） and Ag（ 111 ） surfaces the homoepitaxial 2D islands take on hexagons, while on Pt（111） surface the islands are truncated triangles, and on Cu（100） and Ag（100） surfaces the islands have square shape. These theoretical predictions are in good accordance with the experimental observations . Since calculation of the condensing potentials is independent of the size of islands, this theoretical model could be widely used to predict the shapes of 2D islands on various surfaces.