Relaxation of the step profile for different microscopic mechanisms
Relaxation of the step profile for different microscopic mechanisms
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不同微观机制的台阶轮廓的松弛
DOI：
10.1116/1.588836
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发表时间：
1996
影响因子：
1.4
通讯作者：
E. Williams
中科院分区：
文献类型：
--
作者：
Da‐Jiang Liu;E. Fu;M. Johnson;J. Weeks;E. Williams
对亚稳态结构衰减率的理论和实验研究进行了定量比较。在粗粒度阶梯模型和连续模型中评估了结构的衰变机制、尺寸和周期性对衰变速率的影响。对于高振幅结构，衰减随大小 (N) 和时间变化为 (t/Nα)−β。指数 α 和 β 取决于质量传递机制。对于局部保守扩散通量，尺寸缩放为 α=4；对于局部非保守扩散通量，尺寸缩放为 α=2。对于扩散有限质量传递，时间缩放指数为 β=1/5，对于阶梯附着有限质量传递，时间缩放指数为 β=1/4。实验在高度受控尺寸为 3-5 nm 的亚稳态结构上进行，这些结构是通过对 Si(111) 进行直流加热而制备的。缩放比例（α=4.3±0.5，β=0.2−0.3）和绝对衰减率与理论预测定量一致。
Theoretical and experimental studies of the rate of decay of metastable structures are compared quantitatively. The effect of decay mechanism, size, and periodicity of the structure on the rate of decay is evaluated within both a coarse‐grained step‐based model and a continuum model. For high‐amplitude structures, the decay scales with size (N) and time as (t/Nα)−β. The exponents α and β depend on the mass transport mechanism. The size scaling is α=4 for locally conserved diffusive flux and α=2 for locally nonconserved flux. The time scaling exponent is β=1/5 for diffusive limited mass transport and β=1/4 for step attachment limited mass transport. Experiments were performed on metastable structures of controlled sizes 3–5 nm in height, prepared by direct current heating on Si(111). Quantitative agreement with theoretical predictions of both scaling (α=4.3±0.5, β=0.2−0.3) and absolute rate of decay were obtained.