Mitigating coherent loss in superconducting circuits using molecular self-assembled monolayers

Journal Article · 08 November 2024 · Scientific Reports

DOI: https://doi.org/10.1038/s41598-024-77227-7 · OSTI ID:2481716

Alghadeer, Mohammed ^[1]; Banerjee, Archan ^[2]; Lee, Kyunghoon ^[2]; Hussein, Hussein ^[3]; Fariborzi, Hossein ^[4]; Rao, Saleem ^[5]

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1. University of Oxford (United Kingdom); University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
2. University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
3. American University of Beirut (Lebanon); King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)
4. King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)
5. King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

In planar superconducting circuits, decoherence due to materials imperfections, especially two-level-system (TLS) defects at different interfaces, is a primary hurdle for advancing quantum computing and sensing applications. Traditional methods for mitigating TLS loss, such as etching oxide layers at metal and substrate interfaces, have proven to be inadequate due to the persistent challenge of oxide regrowth. In this work, we introduce a novel approach that employs molecular self-assembled monolayers (SAMs) to chemically bind at different interfaces of superconducting circuits. This technique is specifically tested here on coplanar waveguide (CPW) resonators, in which this method not only impedes oxide regrowth after surface etching but can also tailors the dielectric properties at different resonators interfaces. The deployment of SAMs results in a consistent improvement in the measured quality factors across multiple resonators, surpassing those with only oxide-etched resonators. The efficiency of our approach is supported by microwave measurements of multiple devices conducted at millikelvin temperatures and correlated with detailed X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) characterizations of SAM-passivated resonators. The compatibility of SAMs materials with the established fabrication techniques offers a promising route to improve the performance of superconducting quantum devices.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2481716
• Journal Information: Scientific Reports, Journal Name: Scientific Reports Journal Issue: 1 Vol. 14; ISSN 2045-2322
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United States
• Language: English