Relaxation of crystal shapes caused by step motion
Relaxation of crystal shapes caused by step motion
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步进运动引起的晶体形状松弛
DOI：
10.1143/jpsj.57.1681
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
M. Uwaha
中科院分区：
文献类型：
--
作者：
M. Uwaha
本文从理论上研究了步进运动时α晶面和邻晶面的形状弛豫。当一个平坦的邻面受到扰动时，弛豫时间τ中的波数依赖性的幂由瓶颈过程、台阶运动或扩散决定，比例常数取决于波矢和台阶的相对角度。如果小晶体通过粗糙化过渡进行淬火，当台阶环收缩或膨胀时，就会出现带有小平面的新平衡形状。如果扩散很快，Ds →∞，则逐渐变平，τ <$Rc 2（Rc：二维临界核的半径）。如果台阶迁移率大，η s →∞，输运依赖于慢扩散，则晶体顶部出现小的小面，小面尺寸随着R f ≤ t 1/5而扩大。
Shape relaxation of a crystal faces and of vicinal faces is theoretically studied interms of step movement. When a flat vicinal surface is perturbed, the power of wave number dependence in the relaxation time τ is determined by the bottleneck process, step movement or diffusion, and the proportionality constant depends on the relative angle of the wave vector and the steps. If a small crystal is quenched through a roughening transition, a new equilibrium shape with a facet emerges when the step loops shrink or expand. If diffusion is fast, D s →∞, gradual flattening occurs with τ∝ R c 2 ( R c : radius of the 2D critical nucleus). If the step mobility is large, η s →∞ and the transport relies on slow diffusion, a small facet appears on the top of the crystal and the facet size expands as R f ∝ t 1/5 .