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Phase-dependent microwave response of a graphene Josephson junction

Haller, R.; Fülöp, G.; Indolese, D.; Ridderbos, J.; Kraft, R. 1,2; Cheung, L. Y.; Ungerer, J. H.; Watanabe, K.; Taniguchi, T.; Beckmann, D. 3; Danneau, R. 3; Virtanen, P.; Schönenberger, C.
1 Physikalisches Institut (PHI), Karlsruher Institut für Technologie (KIT)
2 Institut für Nanotechnologie (INT), Karlsruher Institut für Technologie (KIT)
3 Institut für QuantenMaterialien und Technologien (IQMT), Karlsruher Institut für Technologie (KIT)

Abstract:

Gate-tunable Josephson junctions embedded in a microwave environment provide a promising platform to in-situ engineer and optimize novel superconducting quantum circuits. The key quantity for the circuit design is the phase-dependent complex admittance of the junction, which can be probed by sensing an rf SQUID with a tank circuit. Here, we investigate a graphene-based Josephson junction as a prototype gate-tunable element enclosed in a SQUID loop that is inductively coupled to a superconducting resonator operating at 3 GHz. With a concise circuit model that describes the dispersive and dissipative response of the coupled system, we extract the phase-dependent junction admittance corrected for self-screening of the SQUID loop. We decompose the admittance into the current-phase relation and the phase-dependent loss and as these quantities are dictated by the spectrum and population dynamics of the supercurrent-carrying Andreev bound states, we gain insight to the underlying microscopic transport mechanisms in the junction. We theoretically reproduce the experimental results by considering a short, diffusive junction model that takes into account the interaction between the Andreev spectrum and the electromagnetic environment, from which we deduce a lifetime of ~17 ps for non-equilibrium populations.


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DOI: 10.5445/IR/1000145807
Veröffentlicht am 04.05.2022
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Institut für QuantenMaterialien und Technologien (IQMT)
Physikalisches Institut (PHI)
Publikationstyp Forschungsbericht/Preprint
Publikationsmonat/-jahr 03.2022
Sprache Englisch
Identifikator KITopen-ID: 1000145807
HGF-Programm 47.11.02 (POF IV, LK 01) Emergent Quantum Phenomena
Vorab online veröffentlicht am 14.03.2022
Nachgewiesen in arXiv
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