Structure of metallic nanowires and nanoclusters formed in superfluid helium
Structure of metallic nanowires and nanoclusters formed in superfluid helium
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DOI：
10.1134/s1063776111040182
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发表时间：
2011-06-01
影响因子：
1.1
通讯作者：
Khodos, I. I.
中科院分区：
文献类型：
--
作者：
Gordon, E. B.;Karabulin, A. V.;Khodos, I. I.
结果表明，激光烧蚀嵌入HeII中的Ni、Pb、in和Sn靶材时形成的金属纳米线（直径5-8 nm）包含延伸的单晶段，而在这些条件下形成的球形团簇（直径约2 μ m）具有规则的形状和原子光滑的表面。这种结构可以用金属烧蚀产物在HeII中聚结下的熔化来解释。能量为200kev的低强度电子束的短期作用引发了保存在透射电子显微镜真空室中的金属球体的爆炸，并伴随着数千个直径为几纳米的团簇的形成。这种效应是由于液态氦使熔融球体急剧冷却时产生的内部机械应力的亚稳态。提出了原子和纳米粒子在超流氦量子化涡中的凝结机理。
It is shown that metallic nanowires (5-8 nm in diameter) that form during laser ablation of Ni, Pb, In, and Sn targets embedded in HeII contain extended single-crystal segments, while spherical clusters (about 2 mu m in diameter) that form under these conditions have a regular shape and an atomically smooth surface. Such structures are explained by melting of metal ablation products under their coalescence in HeII. The short-term action of a low-intensity beam of electrons with an energy of 200 keV initiates the explosion in metallic spheres preserved in the vacuum chamber of a transmission electron microscope, which is accompanied with the formation of thousands of clusters with a diameter of a few nanometers. This effect is due to metastability of internal mechanical stresses produced upon sharp cooling of molten spheres by liquid helium. A mechanism of condensation of atoms and nanoparticles in quantized vortices of superfluid helium is proposed.