Title: Direct Imaging of Electron Orbitals with a Scanning Transmission Electron Microscope Show Chinese title

Title: 用扫描透射电子显微镜直接成像电子轨道

Abstract: Recent studies of secondary electron (SE) emission in scanning transmission electron microscopes suggest that material's properties such as electrical conductivity, connectivity, and work function can be probed with atomic scale resolution using a technique known as secondary electron e-beam-induced current (SEEBIC). Here, we apply the SEEBIC imaging technique to a stacked 2D heterostructure device to reveal the spatially resolved electron orbital ionization cross section of an encapsulated WSe2 layer. We find that the double Se lattice site shows higher emission than the W site, which is at odds with first-principles modelling of ionization of an isolated WSe2 cluster. These results illustrate that atomic level SEEBIC contrast within a single material is possible and that an enhanced understanding of atomic scale SE emission is required to account for the observed contrast. In turn, this suggests that subtle information about interlayer bonding and the effect on electron orbitals can be directly revealed with this technique. Show Chinese abstract

Abstract: 最近对扫描透射电子显微镜中二次电子（SE）发射的研究表明，使用一种称为二次电子电子束诱导电流（SEEBIC）的技术，可以以原子尺度分辨率探测材料的电导率、连通性和功函数等特性。 在这里，我们将SEEBIC成像技术应用于堆叠的二维异质结构器件，以揭示封装的WSe2层的空间分辨电子轨道电离截面。 我们发现，双硒晶格位点的发射比钨位点更高，这与孤立的WSe2团簇电离的第一性原理建模结果相矛盾。 这些结果表明，在单一材料中实现原子级的SEEBIC对比是可能的，并且需要对原子尺度的SE发射有更深入的理解，以解释观察到的对比度。 反过来，这表明可以通过该技术直接揭示层间键合的细微信息及其对电子轨道的影响。