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TT: Fachverband Tiefe Temperaturen

TT 35: Superconducting Electronics: SQUIDs, Circuit QED

TT 35.4: Talk

Wednesday, March 20, 2024, 10:15–10:30, H 2053

Tunable Superconductor Insulator Transition in a Quantum Phase Slip Interference Device — •Jan Nicolas Voss¹, Micha Wildermuth¹, Max Kristen^1,2, Hannes Rotzinger^1,2, and Alexey V. Ustinov^1,2 — ¹Physikalisches Institut, Karlsruher Institut für Technologie, Karlsruhe, Germany — ²Institut für Quantenmaterialien und Technologien (IQMT), Karlrsruher Institut für Technologie, Karlsruhe, German

The duality between quantum phase slip nanowires and Josephson junctions has triggered a variety of theoretical and experimental works. However, many aspects of these fluctuations are still not fully understood, especially when interference effects are considered.

We present a realization of a quantum phase slip interferometer based on two strongly coupled granular aluminum nanowires connected in series. In the experiment, the interference is controlled by a gate voltage and manifests as a periodic modulation of the critical Coulomb blockade voltage. Our data show that the modulation amplitude depends on the homogeneity of the wires. To improve the wire homogeneity, we employ the intrinsic electromigration technique ([1]) which allows to adjust the resistances and thus the Coulomb blockade of the individual wires. We observe a strong destructive interference of quantum phase slips, displaying a transition from the insulating to a superconducting state. The circuit is analyzed in detail and future applications are proposed.

[1] J. N. Voss, Y. Schön, M. Wildermuth, D. Dorer, J. H. Cole, H. Rotzinger and A. V. Ustinov, ACS Nano (2021) Mar 23;15(3):4108

Keywords: Nanowires; Quantum phase slips; Granular aluminum; Quantum transistor