Hassel and Marianne Ledbetter MatSE Colloquium - "Functional Dislocations: From Charge Carrier-Controlled Deformation to Quantum Interconnects"

As carriers of plasticity, dislocations have been studied extensively in structural materials to understand their structure, mobility, and interactions with other defects. In electronic materials, however, they are widely regarded as detrimental, degrading material quality and impairing device performance. While most research therefore focuses on the limitations dislocations impose on functional materials, this talk highlights the opportunities they offer. We will begin by exploring the coupling between mechanical and electronic properties in II–VI semiconductors, using photoplasticity as an example: a brittle-to-ductile transition that depends on illumination conditions. Using first-principles calculations, we will examine how photo-excited charge carriers affect the dislocation core structure and mobility, and we will discuss experiments designed to test these predictions. We will then turn to a second application where dislocations can be used deliberately to design functionality in quantum-relevant materials and consider their potential as interconnects for spin qubits in diamond and SiC.