Revealing the role of interface disorder in modulating critical current density of Josephson junctions

Abstract Suppressing critical current density ( J c ) 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 J c 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 J c uniformity. We identify a new disorder metric, Interface Bonding Topology Factor (IBTF), that captures bond-angle fluctuations and oxygen-coordination heterogeneity within J c variations. Through multivariate analysis, J c is exponentially correlated with interface disorder and barrier thickness ( d ) by J c ∝ e −IBTF⋅ d , explaining 91.88% of the observed J c 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 provides a device-oriented strategy and a tunable physical metric beyond single-feature control for scalable high-performance quantum processors.