Kinetic inductance in superconducting CoSi$_2$ coplanar microwave transmission lines

Ekaterina Mukhanova; Weijun Zeng; Elica Anne Heredia; Chun-Wei Wu; Ilari Lilja; Juhn-Jong Lin; Sheng-Shiuan Yeh; Pertti Hakonen

arXiv · 2312.14624

Kinetic inductance in superconducting CoSi$_2$ coplanar microwave transmission lines

Ekaterina Mukhanova·Weijun Zeng·Elica Anne Heredia·Chun-Wei Wu·Ilari Lilja·Juhn-Jong Lin·Sheng-Shiuan Yeh·Pertti Hakonen

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Abstract

We have looked into cobalt disilicide (CoSi$_2$) as a potential building block for superconducting quantum circuits. In order to achieve this, we annealed a thin layer of Co to create 10-105 nm thick microwave cavities from CoSi$_2$ embedded in the silicon substrate. The cavity properties were measured as a function of temperature and power. In films measuring 10 and 25 nm, we find a significant kinetic inductance $L_\mathrm{K}$ with a non-BCS power-law variation $\delta L_\mathrm{K} \propto T^{4.3 \pm 0.2}$ at low temperatures. The quality factor of the studied microwave resonances increased almost linearly with thickness, with two-level systems having very little effect. The power dependence of kinetic inductance was analyzed in terms of heat flow due to electron-phonon coupling, which was found stronger than estimated for heat relaxation by regular quasiparticles.

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Ekaterina Mukhanova, Weijun Zeng, Elica Anne Heredia, Chun-Wei Wu, Ilari Lilja, Juhn-Jong Lin, Sheng-Shiuan Yeh, Pertti Hakonen. 2023-12-22. Kinetic inductance in superconducting CoSi$_2$ coplanar microwave transmission lines. https://arxiv.org/abs/2312.14624

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