Chemical and structural identification of material defects in superconducting quantum circuits

Abstract Quantum circuits show unprecedented sensitivity to external fluctuations compared their classical counterparts, and it can take as little a single atomic defect somewhere in mm-sized area completely spoil device performance. For improved coherence is thus essential find ways reduce the number of defects, thereby lowering hardware threshold for achieving fault-tolerant large-scale error-corrected quantum computing. Given evasive nature these materials science required understand them at present uncharted territories, new techniques must be developed bridge existing capabilities from with needs identified by superconducting circuit community. In this paper, we give an overview methods characterising chemical structural properties defects relevant circuits. We cover recent developments in-operation techniques, where are used probes themselves, situ analysis well-established ex techniques. The latter now increasingly explored community correlate specific material qubit highlight which, given further development, look especially promising will contribute towards future toolbox quantum.