3D Visualization of Rare-Earth Dopant Defects and Clustering in SiC Using Multislice Electron Ptychography

Rare earth ions in wide-bandgap materials present a promising platform for quantum information technologies. However, the substantial size mismatch between dopants like samarium (Sm) and the host lattice in materials like silicon carbide (SiC) leads to complex clustering and defect structures that go beyond simple substitutions or vacancies. Dopant clustering – a known mechanism in dopant deactivation – plays a crucial role in modifying material properties, highlighting the need for atomic-scale insights to enhance doping strategies and material performance.

In this study, we apply multislice electron ptychography (MEP) to examine Sm defects and clusters in SiC, which serves as a model for studying rare-earth-doped defect centers. Using advanced high-dynamic range electron detectors, MEP achieves sub-Ångstrom lateral resolution and nanometer-scale depth resolution, making it possible to visualize atomic distributions and subtle features that are missed with traditional techniques. Our analysis has cataloged various defect structures and Sm clusters in SiC, providing detailed insight into their atomic arrangements, including the imaging of samarium silicide nanocrystals embedded in the lattice. Additionally, we present Density Functional Theory (DFT) calculations, offering an understanding of the stability and atomic behavior of Sm dopants and the mechanisms underlying defect formation in high-dopant environments.