SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: Focus Session: Unconventional Transport Phenomena in Low-Dimensional Superconducting Heterostructures

TT 27.8: Vortrag

Mittwoch, 29. März 2023, 12:15–12:30, HSZ 03

Investigation of Nb gate-controlled superconducting nanoscale devices. — •Leon Ruf, Elke Scheer, and Angelo Di Bernardo — 78464 Konstanz, Konstanz Germany

The electrical conductance in nanoscale devices can be modulated by an applied electric field (EF). In semiconductors the charge density is low, and the EF can penetrate deeply. However, in superconductors the charge carrier density is high and the external EF decays exponentially over a short distance. In 2018, it was reported [1] that the superconducting state can be partially and fully suppressed in gated nano constrictions by a strong applied EF which they attribute to an EF induced perturbation of the superconducting state. Since then, the observations were controversially discussed attributing them to an EF effect [1], high-energy quasiparticle injection [2], low-energy-mediated phonon excitation [3] or hot-spot generation [4]. Here, we are studying Nb gated Dayem bridges. Our observations show reversible full suppression of the supercurrent for Nb devices made by lift off, not for geometrically comparable etched devices. We discuss our observations in the light of the suggested mechanisms [1-4].
[1] G. De Simoni et al., Nat. Nanotechnol. 13, 802 (2018)
[2] L. D. Alegria et al., Nat. Nanotechnol. 16, 404 (2021)
[3] M. F. Ritter et al., Nat. Electron. 5, 71 (2022)
[4] J. Basset et al., Phys. Rev. Res. 3, 043169 (2021)