Investigating The Structure of Spin Qubits Using Electron Ptychography

Divacancy and vacancy-transition metal (v-TM) complexes in silicon carbide (SiC) can form the basis for optically addressable single photon emitters. The convergence of SiC's technological maturity and the compatibility of these qubits with traditional semiconductors has thus sparked considerable interest in these defects. For example, recent quantum coherence measurements of v-TM complex spin states in SiC have underscored the potential of this platform in quantum computing applications. To validate theoretical frameworks and glean insights pertinent to emitter synthesis and stability, atomic resolution electron microscopy offers direct access to their structure and interactions within their local environment.<br/> <br/>This presentation will explore the direct observation of individual defects in a SiC film using scanning transmission electron microscopy (STEM) imaging and multislice electron ptychography. We will show how the capabilities afforded by multislice electron ptychography enable us to characterize these defects at a localized level and in 3D without the need for tomography or through-focus methods. Moreover, we will show that conventional methods, such as high-angle annular dark field STEM, can be severely limited for this type of study due to noise and are frequently obscured by surface contamination, damage, and roughness. We will demonstrate that ptychographic reconstructions can directly quantify single defects and defect complexes on a slice-by-slice basis, imparting direct 3D information. This will be explored using simulated ptychographic datasets encompassing an array of defects in various positional configurations. Finally, we will discuss the limitations of capturing three-dimensional structures and the ability to capture small displacements arising from substitution and the formation of v-TM complexes.