Speaker
Description
To understand material properties and functionality at the fundamental level, it is essential to precisely determine their 3D atomic arrangement. For crystalline materials, crystallography can provide this information. However, perfect crystals are rare in nature. Real materials often contain crystal defects, surface reconstructions, nanoscale heterogeneities, and disorders, which strongly influence material properties and performance. Here, we present atomic electron tomography (AET) for 3D structure determination of crystal defects and disordered materials at the single-atom level. By combining the tomographic tilt series acquired from aberration corrected electron microscopes with advanced algorithms [1], we localized the coordinates of individual atoms and point defects in materials with a 3D precision of ~19 pm, and determined full 3D strain tensor [2]. More recently, we determined the 3D coordinates of 6,569 Fe and 16,627 Pt atoms in an FePt nanoparticle, and correlated chemical order/disorder and crystal defects with material properties at the individual atomic level [3].
[1] A. Pryor, Y. Yang et al., Sci. Rep. 7:10409 (2017).
[2] R. Xu et al., Nature Mater. 14, 1099-1103 (2015).
[3] Y. Yang et al., Nature 542, 75-79 (2017).
