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arXiv · 2306.13654

Quasiparticle spectroscopy in technologically-relevant niobium using London penetration depth measurements

Sunil Ghimire·Kamal R. Joshi·Amlan Datta·Aidan Goerdt·Makariy A. Tanatar·Deborah Schlagel·Matthew J. Kramer·Jayss Marshall·Cameron J. Copas·Joshua Y. Mutus·Alexander Romanenko·Anna Grassellino·Ruslan Prozorov
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Abstract

London penetration depth was measured in niobium foils, thin films, single crystals, and superconducting radio-frequency (SRF) cavity pieces cut out from different places. The low-temperature (T<Tc/3) variation, sensitive to the low-energy quasiparticles with states inside the superconducting gap, differs dramatically between different types of samples. With the help of phenomenological modeling, we correlate these different behaviors with known pair-breaking mechanisms and show that such measurements may help distinguish between different pair-breaking mechanisms, such as niobium hydrides and two-level systems (TLS). The conclusions also apply to SRF cavities when tracking the temperature-dependent quality factor and the resonant frequency.

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Sunil Ghimire, Kamal R. Joshi, Amlan Datta, Aidan Goerdt, Makariy A. Tanatar, Deborah Schlagel, Matthew J. Kramer, Jayss Marshall, Cameron J. Copas, Joshua Y. Mutus, Alexander Romanenko, Anna Grassellino, Ruslan Prozorov. 2023-06-23. Quasiparticle spectroscopy in technologically-relevant niobium using London penetration depth measurements. https://doi.org/10.1088/2633-4356%2Fad8c0c

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