Alp Sipahigil (Advisor)

Achieving high-performance quantum computing with superconducting qubits requires a good understanding of the various loss mechanisms that can degrade qubit performance. One such potential loss mechanism is undesired electromechanical coupling mediated by piezoelectric effects. It can occur even in centrosymmetric materials due to interface symmetry breaking. In our recent cryogenic microwave transmission measurements, we observed such interface piezoelectricity at the aluminum-silicon and aluminum-sapphire heterostructures, a widely used material combination in superconducting qubit...

Silicon, a mature platform of modern semiconductor technology, is also emerging as a versatile host for quantum and nanoscale systems. In addition to its low-loss and low-noise properties, silicon can host defects that provide localized states with rich electronic and mechanical responses. In this project, we investigate defect-mediated electromechanical coupling in silicon, where lattice imperfections act as active media connecting electrical and vibrational degrees of freedom. By fabricating high-quality mechanical and superconducting resonators on silicon, we probe how defects influence...