扫描隧道显微镜针尖调制的薄膜表面的原子扩散

摘要

We investigate the scanning tunneling microscopy （STM） tip-modulated atomic motion on the top of Co island and interlayer mass transport on the island edge based on the molecular static （MS） method.Our results show that STM manipulation has an important effect on Co atomic diffusion on the top of Co island and on the island edge.The interaction of the STM tip with the adatom and the strong shape transitions in Co island and in the Cu（001） substrate result in the change of the jump diffusion barrier on the top of the island,the Ehrlich-Schwoebel（E-S） and exchange barrier on the island edge.It is found that by adjusting the distance between the tip and the substrate one can reduce the diffusion barrier of the above three diffusion processes and transform the growth mode of the Co films from 3D to 2D.%采用原子尺度的模拟方法,探讨了在零偏压下扫描隧道显微镜（STM）针尖调制的金属表面岛上原子运动及岛边的层间质量输运.研究结果显示STM的移动对岛上及岛边的原子扩散有重要的影响.针尖与吸附原子的交互作用及岛和基体中强的形状变化影响了岛上吸附原子的跳跃扩散及岛边的跳下扩散和交换扩散过程.研究发现,通过调节针尖与基体的垂直距离及针尖与吸附原子的水平距离,可以降低岛上吸附原子的跳跃扩散能垒及岛边的跳下扩散和交换扩散能垒,从而实现薄膜由三维生长模式向二维生长模式的转变.