Tian Xuezeng, Yan Xingxu, Varnavides Georgios, Yuan Yakun, Kim Dennis S, Ciccarino Christopher J, Anikeeva Polina, Li Ming-Yang, Li Lain-Jong, Narang Prineha, Pan Xiaoqing, Miao Jianwei
Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Sci Adv. 2021 Sep 17;7(38):eabi6699. doi: 10.1126/sciadv.abi6699. Epub 2021 Sep 15.
The three-dimensional (3D) local atomic structures and crystal defects at the interfaces of heterostructures control their electronic, magnetic, optical, catalytic, and topological quantum properties but have thus far eluded any direct experimental determination. Here, we use atomic electron tomography to determine the 3D local atomic positions at the interface of a MoS-WSe heterojunction with picometer precision and correlate 3D atomic defects with localized vibrational properties at the epitaxial interface. We observe point defects, bond distortion, and atomic-scale ripples and measure the full 3D strain tensor at the heterointerface. By using the experimental 3D atomic coordinates as direct input to first-principles calculations, we reveal new phonon modes localized at the interface, which are corroborated by spatially resolved electron energy-loss spectroscopy. We expect that this work will pave the way for correlating structure-property relationships of a wide range of heterostructure interfaces at the single-atom level.
异质结构界面处的三维（3D）局部原子结构和晶体缺陷控制着它们的电子、磁性、光学、催化和拓扑量子特性，但迄今为止尚未有任何直接的实验测定方法。在此，我们使用原子电子断层扫描技术以皮米精度确定了MoS-WSe异质结界面处的3D局部原子位置，并将3D原子缺陷与外延界面处的局部振动特性相关联。我们观察到点缺陷、键畸变和原子尺度的波纹，并测量了异质界面处的完整3D应变张量。通过将实验得到的3D原子坐标作为第一性原理计算的直接输入，我们揭示了定域在界面处的新声子模式，这在空间分辨电子能量损失谱中得到了证实。我们期望这项工作将为在单原子水平上关联广泛的异质结构界面的结构-性质关系铺平道路。
