Building 3D superconductor-based Josephson junctions using a via transfer approach

Abstract

The coupling of superconductivity to unconventional materials may lead to novel quantum states and potential applications. Controlling the quality of the superconductor-normal metal interface is of crucial importance to the understanding and engineering of the superconducting proximity effect. In many cases, conventional lithography-based deposition methods introduce undesirable effects. Using the concept of via contact and dry transfer, we have constructed smooth, van der Waals-like contact between 3D superconducting NbN/Pd and graphene with low contact resistance of approximately 130 $\Omega \cdot \mu m$. Gate-tunable supercurrent, Fraunhofer pattern, and Andreev reflections are observed, the properties of which can be understood using an induced superconducting gap $\Delta$' in this planar contact geometry. We discuss potential mechanisms impacting the magnitude of $\Delta$' and suggest ways of further increasing the proximity coupling. This gentle, lithography-free contacting method can be applied to air- and damage-sensitive surfaces to engineer novel superconducting heterostructures.

23 pages, 4 figures, with Supplemental Information. Comments are welcome

References in corpus (37)

• Bipolar supercurrent in graphene
• $4\pi$-periodic Josephson supercurrent in HgTe-based topological Josephson junctions
• The Josephson critical current in a long mesoscopic S-N-S junction
• Ballistic Josephson junctions in edge-contacted graphene
• Quantum oscillations of the critical current and high-field superconducting proximity in ballistic graphene
• Supercurrent in the quantum Hall regime
• Inducing Superconducting Correlation in Quantum Hall Edge States
• Transparent Semiconductor-Superconductor Interface and Induced Gap in an Epitaxial Heterostructure Josephson Junction
• Universal self-field critical current for thin-film superconductors
• Induced superconductivity in high mobility two dimensional electron gas in GaAs heterostructures
• Gate-Defined Josephson Junctions in Magic-Angle Twisted Bilayer Graphene
• Ballistic graphene Josephson junctions from the short to the long regime
• Highly Tunable Junctions and Nonlocal Josephson Effect in Magic Angle Graphene Tunneling Devices
• Via Method for Lithography Free Contact and Preservation of 2D Materials
• Density of states and supercurrent in diffusive SNS junctions: role of nonideal interfaces and spin-flip scattering
• Observation of Supercurrent in PbIn-Graphene-PbIn Josephson Junction
• Proximity coupling in superconductor-graphene heterostructures
• Superconducting proximity effect in epitaxial Al-InAs heterostructures
• Proximity-Induced Superconductivity in Epitaxial Topological Insulator/Graphene/Gallium Heterostructures
• Frequency dependent superfluid stiffness in the pseudogap regime in strongly disordered NbN thin films
• Evidence for chiral supercurrent in quantum Hall Josephson junctions
• High-Temperature Quantum Valley Hall Effect with Quantized Resistance and a Topological Switch
• Superconducting proximity effect in a transparent van der Waals superconductor-metal junction
• Full range of proximity effect probed with Superconductor/Graphene/Superconductor junctions
• Van der Waals pi Josephson junctions
• Superconductivity in the surface state of noble metal gold and its Fermi level tuning by EuS dielectric
• Planar graphene-NbSe${}_2$ Josephson junctions in a parallel magnetic field
• Signatures of van Hove singularities probed by the supercurrent in a graphene - hBN superlattice
• Gate-Defined Topological Josephson Junctions in Bernal Bilayer Graphene
• Critical current scaling in long diffusive graphene-based Josephson junctions
• Andreev processes in mesoscopic multi-terminal graphene Josephson junctions
• Ballistic Josephson junctions based on CVD graphene
• Revealing intrinsic superconductivity of the Nb/BiSbTe${}_2$Se interface
• High magnetic field stability in a planar graphene-NbSe${}_2$ SQUID
• Tunneling Spectroscopy of Two-Dimensional Materials Based on Via Contacts
• Contact transparency in mechanically assembled 2D material devices
• Engineering superconducting contacts transparent to a bipolar graphene