title: Thermal and quantum depletion of superconductivity in narrow junctions created by controlled electromigration.
abstract: Superconducting nanowires currently attract great interest due to their application in single-photon detectors and quantum-computing circuits. In this context, it is of fundamental importance to understand the detrimental fluctuations of the superconducting order parameter as the wire width shrinks. In this paper, we use controlled electromigration to narrow down aluminium nanoconstrictions. We demonstrate that a transition from thermally assisted phase slips to quantum phase slips takes place when the cross section becomes less than ∼150 nm(2). In the regime dominated by quantum phase slips the nanowire loses its capacity to carry current without dissipation, even at the lowest possible temperature. We also show that the constrictions exhibit a negative magnetoresistance at low-magnetic fields, which can be attributed to the suppression of superconductivity in the contact leads. These findings reveal perspectives of the proposed fabrication method for exploring various fascinating superconducting phenomena in atomic-size contacts.
authors.affiliation: Département de Physique, Université de Liège, B-4000 Sart Tilman, Belgium.
authors.forename: Xavier D A
authors.initials: XD
authors.lastname: Baumans
authors.affiliation: INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Dorin
authors.initials: D
authors.lastname: Cerbu
authors.affiliation: Département de Physique, Université de Liège, B-4000 Sart Tilman, Belgium.
authors.forename: Obaïd-Allah
authors.initials: OA
authors.lastname: Adami
authors.affiliation: INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Vyacheslav S
authors.initials: VS
authors.lastname: Zharinov
authors.affiliation: INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.|IMEC-Interuniversity Microelectronics Centre, Kapeldreef 75, B-3001 Leuven, Belgium.
authors.forename: Niels
authors.initials: N
authors.lastname: Verellen
authors.affiliation: Department of Physics, University Federico II of Naples, Piazzale Tecchio 80, 80125 Naples, Italy.|CNR-SPIN, Piazzale Tecchio 80, 80125 Naples, Italy.
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: Papari
authors.affiliation: INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Jeroen E
authors.initials: JE
authors.lastname: Scheerder
authors.affiliation: INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Gufei
authors.initials: G
authors.lastname: Zhang
authors.affiliation: INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Victor V
authors.initials: VV
authors.lastname: Moshchalkov
authors.affiliation: Département de Physique, Université de Liège, B-4000 Sart Tilman, Belgium.
authors.forename: Alejandro V
authors.initials: AV
authors.lastname: Silhanek
authors.affiliation: INPAC-Institute for Nanoscale Physics and Chemistry, Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
authors.forename: Joris
authors.initials: J
authors.lastname: Van de Vondel