尺寸依赖的生长速率放大纳米晶体中的无穷小不对称性
Size-Dependent Growth Rates Amplify Infinitesimal Asymmetry in Nanocrystals
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中文总结 AI 辅助
该研究开发尺寸依赖的动力学Wulff构造，发现无穷小种子不对称性可被放大为纳米晶体的强不对称形貌，通过二维、三维晶格及FCC种子的模拟揭示了其各向异性生长机制。
中文摘要 AI 辅助
动力学Wulff构造预测，当晶体学等价晶面具有固定生长速率时，会产生对称的非平衡形状。然而，纳米晶体通过有限晶面生长，这些晶面的成核能垒和配体覆盖率取决于晶面尺寸。本文中，我们开发了一种尺寸依赖的动力学构造，表明即使所有对称相关的晶面遵循相同的微观生长规律，无穷小的种子不对称性也能被放大为强不对称的纳米晶体形貌。空间异质的成核速率和边界限制生长产生了取决于尺寸的晶面生长速度，确定性形状演化将这些局部速率转化为全局形状对称性破缺。我们在二维的正方形和三角形晶格以及三维的FCC（面心立方）种子上说明了持续各向异性生长的机制，其中立方八面体可根据放大的晶面面积扰动类型，演化成棒状或四面体。
英文摘要
The kinetic Wulff construction predicts symmetric nonequilibrium shapes when crystallographically equivalent facets share a fixed growth rate. However, nanocrystals grow through finite facets whose nucleation barriers and ligand coverages depend on facet size. Here we develop a size-dependent kinetic construction and show that as a consequence infinitesimal seed asymmetries can be amplified into strongly asymmetric nanocrystal morphologies even when all symmetry-related facets obey the same microscopic growth law. Spatially heterogeneous nucleation rates and boundary limited growth generate facet growth velocities that depend on size, and deterministic shape evolution translates these local rates into global shape symmetry breaking. We illustrate the mechanism of persistent anisotropic growth on square and triangular lattices in two dimensions and on FCC seeds in three dimensions, where cuboctahedra can evolve toward rods or tetrahedra depending on which facet-area perturbations are amplified.
发表机构
- University of California, Berkeley（加州大学伯克利分校）
- Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）
- Kavli Energy NanoSciences Institute（卡弗里纳米科学能源研究所）
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