Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 11: Superconductivity: Poster
TT 11.26: Poster
Montag, 17. März 2025, 15:00–18:00, P4
Broadband kinetic inductance of high impedance superconductors — •Jan Pusskeiler1, Martin Dressel1, Thomas Valentin2, Ameya Nambisan2, Simon Geisert2, Ioan Pop1, 2, and Marc Scheffler1 — 11. Physikalisches Institut, Universität Stuttgart — 2Physikalisches Institut and IQMT, KIT
Kinetic inductance quantifies the intrinsic phase-shifted electrodynamics of superconductors and lies at the heart of superconducting quantum electronics operating at microwave frequencies. Determining the complex impedance Z of disordered and granular superconductors in a frequency range from 10 kHz to 20 GHz using a broadband Corbino reflectometer allows direct observation of the kinetic inductance as a linear contribution to the reactance, Im(Z) = Lkin · ω. By obtaining the broadband kinetic inductance at temperatures deep in the superconducting state, from 1.15 K up to the critical temperature Tc, we can extrapolate the zero-temperature kinetic inductance.
We study granular aluminum as a high-kinetic inductance superconductor featuring a superconducting dome in the low-temperature phase diagram as a function of normal-state resistivity ρdc. We report kinetic inductances ranging from 20 pH/sq to 2 nH/sq for granular aluminum thin films with resistivities between 120 µΩcm and 6100 µΩcm. We calculate the superfluid stiffness and observe a 1/ρdc dependance, as also reported in [1]. Furthermore, we observe absorption features that we interpret as signatures of collective modes of the superfluid condensate.
[1] U. S. Pracht et al., Phys. Rev. B 93, 100503(R) (2016)
Keywords: kinetic inductance; broadband microwave spectroscopy; Corbino spectroscopy; microwave calibration; granular aluminum