Electric field imaging of single atoms.
Electric field imaging of single atoms.
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DOI：
10.1038/ncomms15631
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发表时间：
2017-05-30
影响因子：
16.6
通讯作者：
Ikuhara Y
中科院分区：
文献类型：
--
作者：
Shibata N;Seki T;Sánchez-Santolino G;Findlay SD;Kohno Y;Matsumoto T;Ishikawa R;Ikuhara Y
在扫描电子显微镜(STEM)中，单原子可以通过使用样品后环形探测器探测通过高角度散射的电子来成像。最近的研究表明，用原子分辨差分相衬扫描电子显微镜可以探测晶体材料中正原子核和周围负电子的原子尺度电场。在这里，我们演示了使用亚空间分辨率STEM结合高速分段探测器对单个Au原子内(投射的)原子电场分布的真实空间成像。我们直接可视化地看到，单个Au原子内的电场分布(被亚尺寸电子探针模糊)发生了剧烈的变化，其形状与原子内总电荷密度的空间变化有关。具有单原子灵敏度的原子分辨电场映射使我们能够检查它们详细的内部和边界结构。扫描电子显微镜(STEM)成像单个原子的能力正变得越来越复杂。在这里，作者使用差分相位对比STEM来绘制单个Au原子和SrTiO_3晶体内部的原子电场图，这是向将这种原子内和原子间的电子结构可视化为化学键迈出的一步。
In scanning transmission electron microscopy (STEM), single atoms can be imaged by detecting electrons scattered through high angles using post-specimen, annular-type detectors. Recently, it has been shown that the atomic-scale electric field of both the positive atomic nuclei and the surrounding negative electrons within crystalline materials can be probed by atomic-resolution differential phase contrast STEM. Here we demonstrate the real-space imaging of the (projected) atomic electric field distribution inside single Au atoms, using sub-Å spatial resolution STEM combined with a high-speed segmented detector. We directly visualize that the electric field distribution (blurred by the sub-Å size electron probe) drastically changes within the single Au atom in a shape that relates to the spatial variation of total charge density within the atom. Atomic-resolution electric field mapping with single-atom sensitivity enables us to examine their detailed internal and boundary structures. The ability of scanning transmission electron microscopy (STEM) to image single atoms is becoming increasingly sophisticated. Here, the authors use differential phase contrast STEM to map the atomic electric fields within single Au atoms and SrTiO3 crystals, a step toward visualizing such intra- and interatomic electronic structure as chemical bonds.