Abstract Compositional segregation is commonly observed during the growth of III-V alloys in core-shell nanowires. Nanometer-thin stripes, enriched in one of the alloy components, are observed along the six directions perpendicular to the [1 1 1]-wire axis, departing from the core to the outer shell edges in between the {1 1 0} faceted sidewalls. While it has been well established that the phenomenon occurs because of the different mobility of the alloy components, the actual mechanisms by which it happens are yet unclear. A phase-field model, coupling deposition and surface diffusion dynamics, is here developed to inspect the simultaneous evolution of the shell morphology and composition during growth. Both surface energy anisotropy and orientation-dependent growth rates are taken into account to identify their different role. Simulations reveal that the observed segregation is mainly triggered by the enhanced growth rate at the facet edges, while surface anisotropy keeps the stripes thin. Polarity effects are also included to differentiate the behavior between A and B orientations, so to reproduce the experimental observation of a 3-fold symmetry.

中文翻译：

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核壳纳米线中动力学分离的旭日图案：相场研究

摘要 III-V 族合金在核壳纳米线中的生长过程中通常会观察到成分偏析。沿垂直于 [1 1 1] 线轴的六个方向观察到富含其中一种合金成分的纳米细条纹，从核心到 {1 1 0} 刻面侧壁之间的外壳边缘. 虽然这种现象的发生是由于合金成分的不同流动性而产生的，但其发生的实际机制尚不清楚。这里开发了一个相场模型，耦合沉积和表面扩散动力学，以检查生长过程中壳形态和成分的同时演变。表面能各向异性和取向相关的增长率都被考虑在内，以确定它们的不同作用。模拟表明，观察到的偏析主要是由小平面边缘处的增长速度加快引发的，而表面各向异性使条纹保持细长。还包括极性效应以区分 A 和 B 方向之间的行为，从而重现 3 重对称性的实验观察。