Atomistic structure inversion and theoretical modeling of nanoscale defects from STEM images

Accurate atomistic structure capturing local disorder and defects in nanoscale systems is crucial to gain fundamental insights into the structure-property relationship for electronic and quantum applications. We use structure inversion software tools, Ingrained [1] and FANTASTX (Fully Automated Nanoscale To Atomistic Structure from Theory and eXperiments), developed in our group to determine the atomistic structure from experimental STEM images. In this talk, I will discuss two separate applications. First, I will show the evolutionary approach to determine the 3D structure of step defect in Al/Si interface capturing the local disorder using FANTASTX software. Second, we conducted structure search to identify the defect structures in free-standing hexagonal boron nitride responsible for bright, and stable emissions observed in cathodoluminescence experiments. By determining the structure, we theoretically predict the defect levels in the band gap using charge defect calculations to validate the structural origins of the observed properties.

[1] E. Schwenker, V. S. C. Kolluru, et. al., Ingrained: An Automated Framework for Fusing Atomic-Scale Image Simulations into Experiments. Small 2022