[Monthly Seminar] 2026.06.12, 11:00-12:00, Natural Sciences 1, 31317, SKKU

- Title : Engineering Josephson Junctions for Scalable Superconducting Qubits

- Speaker : Dae-Yun Kim (Department of Physics, Ewha Womans University)

- Abstract : Superconducting qubits are a leading platform for scalable quantum processors, but their performance and yield are strongly limited by the controllability of Josephson junctions. In this talk, I will discuss recent progress in Josephson junction engineering for scalable superconducting qubits.

First, I will show that conventional area-based scaling of junction resistance is insufficient for shadow-evaporated Al/AlOx/Al junctions, where finite edge effects and three-dimensional geometry become important. A geometry-aware conductance model incorporating plateau and edge contributions significantly improves resistance prediction. Second, I will discuss how prior fabrication history, such as lift-off and dry etching, modifies weak-link formation through changes in surface morphology and local tunnel-barrier disorder.

Finally, I will briefly introduce spintronics-inspired qubit concepts, including non-volatile, discrete, and multiplexed qubit-frequency tuning. These results highlight Josephson junction engineering as a key route toward scalable and controllable superconducting quantum processors.