title: Magnetically-driven colossal supercurrent enhancement in InAs nanowire Josephson junctions.
abstract: The Josephson effect is a fundamental quantum phenomenon where a dissipationless supercurrent is introduced in a weak link between two superconducting electrodes by Andreev reflections. The physical details and topology of the junction drastically modify the properties of the supercurrent and a strong enhancement of the critical supercurrent is expected to occur when the topology of the junction allows an emergence of Majorana bound states. Here we report charge transport measurements in mesoscopic Josephson junctions formed by InAs nanowires and Ti/Al superconducting leads. Our main observation is a colossal enhancement of the critical supercurrent induced by an external magnetic field applied perpendicular to the substrate. This striking and anomalous supercurrent enhancement cannot be described by any known conventional phenomenon of Josephson junctions. We consider these results in the context of topological superconductivity, and show that the observed critical supercurrent enhancement is compatible with a magnetic field-induced topological transition.
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
authors.forename: J
authors.initials: J
authors.lastname: Tiira
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Strambini
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.|Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 OFS, UK.
authors.forename: M
authors.initials: M
authors.lastname: Amado
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Roddaro
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: San-Jose
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
authors.forename: R
authors.identifier: 0000-0002-7464-7363
authors.initials: R
authors.lastname: Aguado
authors.affiliation: Centro de Fisica de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, E-20018 San Sebastian, Spain.|Donostia International Physics Center (DIPC), E-20018 San Sebastian, Spain.
authors.forename: F S
authors.initials: FS
authors.lastname: Bergeret
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
authors.forename: D
authors.identifier: 0000-0003-2556-0736
authors.initials: D
authors.lastname: Ercolani
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Sorba
authors.affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Giazotto