Investigation of microwave loss induced by oxide regrowth in high-Q Nb resonators
J. Verjauw, A. Potočnik, M. Mongillo, R. Acharya, F. Mohiyaddin, G. Simion, A. Pacco, Ts. Ivanov, D. Wan, A. Vanleenhove, L. Souriau, J. Jussot, A. Thiam, J. Sw… 展开作者
J. Verjauw, A. Potočnik, M. Mongillo, R. Acharya, F. Mohiyaddin, G. Simion, A. Pacco, Ts. Ivanov, D. Wan, A. Vanleenhove, L. Souriau, J. Jussot, A. Thiam, J. Swerts, X. Piao, S. Couet, M. Heyns, B. Govoreanu, I. Radu
最先进的超导量子比特器件的相干性主要受到主要在非晶界面层处发现的两能级系统缺陷的限制。通过适当的表面处理减少这些界面的微波损耗是推动器件性能向前发展的关键。在这里，我们研究铌谐振器去除原生氧化物与氢氟酸蚀刻后。我们调查的再现微波损耗引入的表面氧化物暴露于周围环境后生长。我们发现，在量子器件的损失减少了一个数量级，内部Q-因子达到7 $\cdot$ 10 $^6$在单光子制度，当设备暴露于环境条件下16分钟。此外，我们观察到，Nb 2 O 5是唯一的表面氧化物，在第一个200小时内显着增长，以下扩展Cabrera-莫特生长模型。此时，微波损耗与Nb $_2$ O $_5$厚度成线性比例，提取的损耗角正切tan $δ$ = 9.9 $\cdot$ 10 $^{-3}$。我们的研究结果是特别感兴趣的设备跨越从超导量子比特，量子限制放大器，微波动力学电感探测器单光子探测器。
英文摘要：
The coherence of state-of-the-art superconducting qubit devices is predominantly limited by two-level-system defects, found primarily at amorphous interface layers. Reducing microwave loss from these interfaces by proper surface treatments is key to push the device performance forward. Here, we study niobium resonators after removing the native oxides with a hydrofluoric acid etch. We investigate the reappearance of microwave losses introduced by surface oxides that grow after exposure to the ambient environment. We find that losses in quantum devices are reduced by an order of magnitude, with internal Q-factors reaching up to 7 $\cdot$ 10$^6$ in the single photon regime, when devices are exposed to ambient conditions for 16 min. Furthermore, we observe that Nb2O5 is the only surface oxide that grows significantly within the first 200 hours, following the extended Cabrera-Mott growth model. In this time, microwave losses scale linearly with the Nb$_2$O$_5$ thickness, with an extracted loss tangent tan$δ$ = 9.9 $\cdot$ 10$^{-3}$. Our findings are of particular interest for devices spanning from superconducting qubits, quantum-limited amplifiers, microwave kinetic inductance detectors to single photon detectors.
High temporal stability of niobium superconducting resonators by surface passivation with organophosphonate self-assembled monolayers
Technical University of Munich（慕尼黑工业大学）；Fraunhofer Institute for Electronic Microsystems and Solid-State Technologies（弗劳恩霍夫电子微系统和固态技术研究所）；Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften（瓦尔特·迈斯纳研究所，巴伐利亚科学院）
Enhanced Tantalum Superconducting Resonator Performance via All-Surface Organic Monolayer Passivation
Technical University of Munich（慕尼黑工业大学）；Indian Institute of Technology Roorkee（罗克基印度理工学院）；Fraunhofer Institute for Electronic Microsystems and Solid State Technologies (EMFT)（弗劳恩霍夫电子微系统和固态技术研究所）
In situ Al$_2$O$_3$ passivation of epitaxial tantalum and aluminum films enables long-term stability in superconducting microwave resonators
Grad. Institute of Applied Physics and Dept. of Physics, National Taiwan University（国立台湾大学应用物理研究所及物理系）；Department of Physics, National Tsing Hua University（国立清华大学物理系）；National Synchrotron Radiation Research Center（国家同步辐射研究中心）；Taiwan Semiconductor Research Institute（台湾半导体研究院）
Surface Optimization of Superconducting Aluminum Resonators for Robust Quantum Device Fabrication
Fraunhofer Institut für Elektronische Mikrosysteme und Festkörpertechnologien EMFT（弗劳恩霍夫电子微系统和固态技术研究所）；Center Integrated Sensor Systems (SENS), Universität der Bundeswehr München（联邦国防大学慕尼黑集成传感器系统中心）
Disentangling superconductor and dielectric microwave losses in sub-micron $\rm Nb$/$\rm TEOS-SiO_2$ interconnects using a multi-mode microstrip resonator
Enhanced spectral range of strain-induced tuning of quantum dots in circular Bragg grating cavities
Julius-Maximilians-Universität Würzburg（维尔茨堡大学）；Würzburg-Dresden Cluster of Excellence ct.qmat（维尔茨堡-德累斯顿卓越集群 ct.qmat）；University of Freiburg（弗莱堡大学）；Centre for Nanosciences and Nanotechnologies CNRS, Universite Paris-Saclay（巴黎萨克雷大学法国国家科学研究中心纳米科学与技术中心）；Karlsruhe Institute of Technology (KIT)（卡尔斯鲁厄理工学院）
