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TT: Fachverband Tiefe Temperaturen

TT 6: Superconductivity: Tunnelling and Josephson Junctions I

TT 6.10: Talk

Monday, March 18, 2024, 12:15–12:30, H 3010

Performance study of gate-controlled superconducting currents in Nb devices — •Leon Ruf, Jennifer Koch, Elke Scheer, and Angelo Di Bernardo — University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany

Gate controlled superconductivity (GCS) has recently attracted great attention. It was reported [1] that the superconducting state can be suppressed in gated nanoconstrictions by a gate voltage. The authors attribute their observation to an electric field induced perturbation of the superconducting state, giving the next milestone for future superconducting and CMOS compatible transistors. However, the mechanism for the GCS effect is strongly under debate. Other works report about different mechanism caused by a leakage current: high-energy quasiparticle injection [2], low-energy mediated phonon excitation [3] or hot-spot generation [4]. Here we are studying the performance of Nb Dayem bridges made by electron beam lithography and lift off. Our observations show the GCS effect also for relatively large bridges increasing the critical current. We observe a linear anticorrelation between the critical current and the amplitude of the gate leakage current. We discuss our findings in the light of the suggested mechanism [1-4].

[1] G. De Simoni et al., Nat. Nanotechnol. 13 (2018) 802

[2] L.D. Alegria et al., Nat. Nanotechnol. 16 (2021) 404

[3] M.F. Ritter et al. Nat. Electron. 5 (2022) 71

[4] J. Basset, et al. Phys. Rev. Research 3 (2021) 043169

Keywords: Gate controlled superconductivity; Dayem bridges