Defects in materials give rise to fluctuations in electrostatic fields that reflect the local charge density, but imaging this with single atom sensitivity is challenging. However, if possible, this provides information about the energetics of adatom binding, localized conduction channels, molecular functionality and their relationship to individual bonds. Here, ultrastable electron-optics are combined with a high-speed 2D electron detector to map electrostatic fields around individual atoms in 2D monolayers using 4D scanning transmission electron microscopy. Simultaneous imaging of the electric field, phase, annular dark field and the total charge in 2D MoS₂ and WS₂ is demonstrated for pristine areas and regions with 1D wires. The in-gap states in sulphur line vacancies cause 1D electron-rich channels that are mapped experimentally and confirmed using density functional theory calculations. We show how electrostatic fields are sensitive in defective areas to changes of atomic bonding and structural determination beyond conventional imaging.

材料上的缺陷会引起静电场的波动，该波动反映了局部电荷密度，但是用单原子灵敏度对其进行成像具有挑战性。但是，如果可能的话，这将提供有关吸附原子的能量，局部传导通道，分子功能及其与单个键的关系的信息。在这里，超稳定电子光学与高速2D电子检测器结合使用4D扫描透射电子显微镜在2D单层中围绕单个原子映射静电场。同时对2D MoS ₂和WS ₂中的电场，相位，环形暗场和总电荷进行成像已针对带有一维线的原始区域和区域进行了演示。硫线空位中的能隙状态导致一维富电子通道，该通道可通过实验进行映射并使用密度泛函理论计算得到证实。我们展示了静电场如何在缺陷区域中对原子键的变化和结构确定（超出常规成像）敏感。