Revealing the Role of Interface Disorder in Modulating Critical Current Density of Josephson Junctions

Abstract Suppressing critical current density (Jc) fluctuations in Josephson junctions is essential for improving the reproducibility and scalability of superconducting quantum processors. Despite many elucidations of microscopic mechanisms, the physical modulation of Jc by atomic-scale disorder at the metal-insulator interface remains elusive. Here, we reveal that interfacial bonding topology distortions are the dominant source that regulates Jc uniformity. We identify a new disorder metric, Interface Bonding Topology Factor (IBTF), that captures bond-angle fluctuations and oxygen-coordination heterogeneity within Jc variations. Through multivariate analysis, Jc is exponentially correlated with interface disorder and barrier thickness (d) by Jc ∝ e-IBTF· d$, explaining 91.88% of observed Jc inhomogeneity. We establish IBTF as a tunable physical degree of freedom whose suppression efficacy enhances significantly with increasing d, and demonstrate its active modulation by twin boundary engineering in electrodes. This work would provide atomic-level strategies beyond single-feature control for scalable high-performance quantum processors.