title: Hard Superconducting Gap in InSb Nanowires.
abstract: Topological superconductivity is a state of matter that can host Majorana modes, the building blocks of a topological quantum computer. Many experimental platforms predicted to show such a topological state rely on proximity-induced superconductivity. However, accessing the topological properties requires an induced hard superconducting gap, which is challenging to achieve for most material systems. We have systematically studied how the interface between an InSb semiconductor nanowire and a NbTiN superconductor affects the induced superconducting properties. Step by step, we improve the homogeneity of the interface while ensuring a barrier-free electrical contact to the superconductor and obtain a hard gap in the InSb nanowire. The magnetic field stability of NbTiN allows the InSb nanowire to maintain a hard gap and a supercurrent in the presence of magnetic fields (∼0.5 T), a requirement for topological superconductivity in one-dimensional systems. Our study provides a guideline to induce superconductivity in various experimental platforms such as semiconductor nanowires, two-dimensional electron gases, and topological insulators and holds relevance for topological superconductivity and quantum computation.
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Önder
authors.identifier: 0000-0002-3116-4054
authors.initials: Ö
authors.lastname: Gül
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Folkert K
authors.initials: FK
authors.lastname: de Vries
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Jasper
authors.initials: J
authors.lastname: van Veen
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Kun
authors.initials: K
authors.lastname: Zuo
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Vincent
authors.initials: V
authors.lastname: Mourik
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Sonia
authors.initials: S
authors.lastname: Conesa-Boj
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.|Faculty of Physics and Applied Computer Science, AGH University of Science and Technology , al. A. Mickiewicza 30, 30-059 Kraków, Poland.
authors.forename: Michał P
authors.initials: MP
authors.lastname: Nowak
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: David J
authors.initials: DJ
authors.lastname: van Woerkom
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Netherlands Organisation for Applied Scientific Research (TNO) , 2600 AD Delft, The Netherlands.
authors.forename: Marina
authors.initials: M
authors.lastname: Quintero-Pérez
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Maja C
authors.initials: MC
authors.lastname: Cassidy
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Attila
authors.initials: A
authors.lastname: Geresdi
authors.affiliation: Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.
authors.forename: Sebastian
authors.identifier: 0000-0002-6606-9110
authors.initials: S
authors.lastname: Koelling
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.|Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.
authors.forename: Diana
authors.identifier: 0000-0002-6371-8285
authors.initials: D
authors.lastname: Car
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.|CNRS-Laboratoire d'Analyse et d'Architecture des Systèmes (LAAS), Université de Toulouse , 7 avenue du colonel Roche, F-31400 Toulouse, France.
authors.forename: Sébastien R
authors.initials: SR
authors.lastname: Plissard
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.|CNRS-Laboratoire d'Analyse et d'Architecture des Systèmes (LAAS), Université de Toulouse , 7 avenue du colonel Roche, F-31400 Toulouse, France.
authors.forename: Erik P A M
authors.identifier: 0000-0002-8264-6862
authors.initials: EP
authors.lastname: Bakkers
authors.affiliation: QuTech, Delft University of Technology , 2600 GA Delft, The Netherlands.|Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.|Microsoft Station Q Delft , 2600 GA Delft, The Netherlands.
authors.forename: Leo P
authors.initials: LP
authors.lastname: Kouwenhoven
keywords: InSb; Majorana; hard gap; hybrid device; semiconductor nanowire; topological superconductivity