五氧化二铌中的氧空位作为超导铌中两能级系统损耗的来源
Oxygen Vacancies in Niobium Pentoxide as a Source of Two-Level System Losses in Superconducting Niobium
AI总结：
本文通过原位真空烘烤与ToF-SIMS分析，揭示五氧化二铌中氧空位是超导铌谐振器和transmon量子比特中两能级系统损耗及退相干的主要来源。
摘要：
我们确定了由氧化铌构成的三维超导射频（SRF）谐振器和二维transmon量子比特中量子退相干的一个主要来源：五氧化二铌中的氧空位，这些空位驱动两能级系统（TLS）损耗。通过利用飞行时间二次离子质谱（ToF-SIMS）探测连续原位真空烘烤处理对块体Nb SRF谐振器射频性能以及对代表性Nb样品氧化物结构的影响，我们发现腔体品质因数$Q_0$的非单调演化，该演化与Nb\ extsubscript{2}O\ extsubscript{5}空位产生和氧化物厚度减薄之间的相互作用相关。我们将这一效应定位于氧化物本身，并通过湿法氧化重新生长新的氧化物，揭示了扩散到下层Nb中的间隙氧所起的作用并不显著，重新生长氧化物后加剧的TLS损耗得到缓解。我们假设五氧化二铌中的此类空位充当磁性杂质，并且是TLS驱动的射频损耗的一个来源。
英文摘要：
We identify a major source of quantum decoherence in three-dimensional superconducting radio-frequency (SRF) resonators and two-dimensional transmon qubits composed of oxidized niobium: oxygen vacancies in the niobium pentoxide which drive two-level system (TLS) losses. By probing the effect of sequential \textit{in situ} vacuum baking treatments on the RF performance of bulk Nb SRF resonators and on the oxide structure of a representative Nb sample using time-of-flight secondary ion mass spectrometry (ToF-SIMS), we find a non-monotonic evolution of cavity quality factor $Q_0$ which correlates with the interplay of Nb\textsubscript{2}O\textsubscript{5} vacancy generation and oxide thickness reduction. We localize this effect to the oxide itself and present the insignificant role of diffused interstitial oxygen in the underlying Nb by regrowing a new oxide \textit{via} wet oxidation which reveals a mitigation of aggravated TLS losses. We hypothesize that such vacancies in the pentoxide serve as magnetic impurities and are a source of TLS-driven RF loss.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
