Nb/InAs nanowire proximity junctions from Josephson to quantum dot regimes. (20th January 2017)

• Record Type: Journal Article
• Authors: Gharavi, Kaveh; Holloway, Gregory W; LaPierre, Ray R; Baugh, Jonathan
• Is Part Of: Nanotechnology. Volume 28:Number 8(2017)
• Publication Date: 2017-01-20
• Subjects: nanowires -- proximity effect -- Josephson junction -- InAs -- Andreev reflection -- quantum dots; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/aa5643
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: The superconducting proximity effect is probed experimentally in Josephson junctions fabricated with InAs nanowires contacted by Nb leads. Contact transparencies t ∼ 0.7 are observed. The electronic phase coherence length at low temperatures exceeds the channel length. However, the elastic scattering length is a few times shorter than the channel length. Electrical measurements reveal two regimes of quantum transport: (i) the Josephson regime, characterised by a dissipationless current up to ∼100 nA, and (ii) the quantum dot (QD) regime, characterised by the formation of Andreev bound states (ABS) associated with spontaneous QDs inside the nanowire channel. In regime (i), the behaviour of the critical current I c versus an axial magnetic field B ∣ ∣ shows an unexpected modulation and persistence to fields > 2 T. In the QD regime, the ABS are modelled as the current-biased solutions of an Anderson-type model. The applicability of devices in both transport regimes to Majorana fermion experiments is discussed.