表面三维纳米结构在衰变过程中的层间质量传输机制

DECAY CHARACTERISTICS OF SURFACE 3-DIMENSIONAL NANOSTRUCTURES WITH CONTRACTING INTERLAYER MASS TRANSPORT MECHANISMS

文章研究了三维纳米结构的稳定性和退化机制 ,提出了两种层间传输机制 :any sitedescent(ASD)机制和selective-sitedescent(SSD)机制 ,并用动力学蒙特卡罗模拟方法研究了这两个理论模型 .结果表明 ,ASD和SSD机制为目前关于fcc(111)和fcc(10 0 )表面上的三维纳米结构的形成、表面形貌演化和稳定性提供了一个微观尺度上的深入理解 .

Two types of descent mechanisms are proposed to study the stability and decay of 3-dimensional nanostructures. The first is when an upper atom can easily descend from any edge site by an any-site descent (ASD) mechanism. The other is when the atom has to descend primarily by selective-site descent (SSD) through some particular site such as a kinked site. We have studied the two different interlayer mass transport mechanisms by kinetic Monte Carlo simulation. It is found that if the islands decay primarily via ASD, an optimal island slope and a constant terrace width will be selected. In contrast, SSD gives rise to a gradual increase in the island slope. These generic conclusions provide the basis for a microscopic understanding of the morphological evolution observed in existing experimental studies of island smoothing for a variety of systems, as well as the decay of 3D Cu islands on the (100) and (111) surfaces of Cu observed in the present study.