Structure and Formation Mechanisms in Tantalum and Niobium Oxides in Superconducting Quantum Circuits.

ABSTRACT: Improving the qubit's lifetime (T₁) is crucial for fault-tolerant quantum computing. Recent advancements have shown that replacing niobium (Nb) with tantalum (Ta) as the base metal significantly increases T₁, likely due to a less lossy native surface oxide. However, understanding the formation mechanism and nature of both surface oxides is still limited. Using aberration-corrected transmission electron microscopy and electron energy loss spectroscopy, we found that Ta surface oxide has fewer suboxides than Nb oxide. We observed an abrupt oxidation state transition from Ta₂O₅ to Ta, as opposed to the gradual shift from Nb₂O₅, NbO₂, and NbO to Nb, consistent with thermodynamic modeling. Additionally, amorphous Ta

SUBMITTER: Oh JS 

PROVIDER: S-EPMC11295204 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature