Electrostatic Field-Driven Supercurrent Suppression in Ionic-Gated Metallic Superconducting Nanotransistors

• Published in: Nano letters Vol. 21; no. 24; pp. 10309 - 10314
• Main Authors: Paolucci, Federico, Crisá, Francesco, De Simoni, Giorgio, Bours, Lennart, Puglia, Claudio, Strambini, Elia, Roddaro, Stefano, Giazotto, Francesco
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22-12-2021
• Subjects: Field-effect; superconductivity; electric field; electrolytes; transistor
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.1c03481

Recent experiments have shown the possibility of tuning the transport properties of metallic nanosized superconductors through a gate voltage. These results renewed the longstanding debate on the interaction between electrostatic fields and superconductivity. Indeed, different works suggested competing mechanisms as the cause of the effect: an unconventional electric field-effect or quasiparticle injection. Here, we provide conclusive evidence for the electrostatic-field-driven control of the supercurrent in metallic nanosized superconductors, by realizing ionic-gated superconducting field-effect nanotransistors (ISFETs) where electron injection is impossible. Our Nb ISFETs show giant suppression of the superconducting critical current of up to ∼45%. Moreover, the bipolar supercurrent suppression observed in different ISFETs, together with invariant critical temperature and normal-state resistance, also excludes conventional charge accumulation/depletion. Therefore, the microscopic explanation of this effect calls upon a novel theory able to describe the nontrivial interaction of static electric fields with conventional superconductivity.