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arXiv · 2405.13688

Vibrational modes as the origin of dielectric loss at 0.27$\unicode{x2013}$100 THz in a-SiC:H

B. T. Buijtendorp·A. Endo·W. Jellema·K. Karatsu·K. Kouwenhoven·D. Lamers·A. J. van der Linden·K. Rostem·M. Veen·E. J. Wollack·J. J. A. Baselmans·S. Vollebregt
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Abstract

Low-loss deposited dielectrics are beneficial for the advancement of superconducting integrated circuits for astronomy. In the microwave band ($\mathrm{\sim}$1$\unicode{x2013}$10 GHz) the cryogenic and low-power dielectric loss is dominated by two-level systems. However, the origin of the loss in the millimeter-submillimeter band ($\mathrm{\sim}$0.1$\unicode{x2013}$1 THz) is not understood. We measured the loss of hydrogenated amorphous SiC (a-SiC:H) films in the 0.27$\unicode{x2013}$100 THz range using superconducting microstrip resonators and Fourier-transform spectroscopy. The agreement between the loss data and a Maxwell-Helmholtz-Drude dispersion model suggests that vibrational modes above 10 THz dominate the loss in the a-SiC:H above 200 GHz.

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B. T. Buijtendorp, A. Endo, W. Jellema, K. Karatsu, K. Kouwenhoven, D. Lamers, A. J. van der Linden, K. Rostem, M. Veen, E. J. Wollack, J. J. A. Baselmans, S. Vollebregt. 2024-05-22. Vibrational modes as the origin of dielectric loss at 0.27$\unicode{x2013}$100 THz in a-SiC:H. https://doi.org/10.1103/physrevapplied.23.014035

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