Correlating 3D atomic defects and electronic properties of 2D materials with picometer precision


Xuezeng Tian, Dennis S. Kim, Shize Yang, Christopher J. Ciccarino, Yongji Gong, Yongsoo Yang, Yao Yang, Blake Duschatko, Yakun Yuan, Pulickel M. Ajayan, Juan-Carlos Idrobo, Prineha Narang, and Jianwei Miao. 2/26/2019. “Correlating 3D atomic defects and electronic properties of 2D materials with picometer precision.” arXiv. Publisher's Version


Two-dimensional (2D) materials and heterostructures exhibit exceptional electronic, optical and chemical properties, promising to find applications ranging from electronics and photovoltaics to quantum information science. However, the exceptional properties of these materials strongly depend on their 3D atomic structure especially crystal defects. Using Re-doped MoS2 as a model, we develop scanning atomic electron tomography (sAET) to determine the atomic positions and crystal defects such as dopants, vacancies and ripples with a 3D precision down to 4 picometers. We measure the full 3D strain tensor and quantify local strains induced by single dopants. By directly providing experimental 3D atomic coordinates to density functional theory (DFT), we obtain more truthful electronic band structures than those derived from conventional DFT calculations relying on relaxed 3D atomic models, which is confirmed by photoluminescence spectra measurements. Furthermore, we observe that the local strain induced by atomic defects along the z-axis is larger than that along the x- and y-axis and thus more strongly affects the electronic property of the 2D material. We anticipate that sAET is not only generally applicable to the determination of the 3D atomic coordinates of 2D materials, heterostructures and thin films, but also could transform ab initio calculations by using experimental atomic coordinates as direct input to reveal more realistic physical, material, chemical and electronic properties.