Correlating 3D atomic defects and electronic properties of 2D transition metal dichalcogenides with picometer precision

The field of research in two-dimensional (2D) transition metal dichalcogenides (TMD), has experienced extraordinary growth. To understand the structure-property relationship of these materials at the fundamental level, we must know their 3D atomic structure with high precision.
Here, we developed scanning atomic electron tomography (sAET) to localize the 3D atomic coordinates in 2D materials and heterostructures with picometer precision. Using a Re-doped MoS₂ monolayer sample, we demonstrated a general sAET method to overcome several limitations and determined the 3D coordinates of individual atoms with precision down to 4 pm. We identified 3D crystal defects such as dopants, vacancies and atomic-scale ripples and measured the 3D atomic displacement and the full strain tensor of the Re-doped MoS₂. Furthermore, the experimental 3D atomic coordinates were used as direct input to DFT to correlate crystal defects with the electronic band structure at the single-atom level.
sAET is generally applicable to the determination of the 3D atomic coordinates of various 2D materials, heterostructures and thin films.