Incipient Berezinskii-Kosterlitz-Thouless transition in two-dimensional coplanar Josephson junctions

Abstract

Superconducting hybrid junctions are revealing a variety of novel effects. Some of them are due to the special layout of these devices, which often use a coplanar configuration with relatively large barrier channels and the possibility of hosting Pearl vortices. A Josephson junction with a quasi ideal two-dimensional barrier has been realized by growing graphene on SiC with Al electrodes. Chemical Vapor Deposition offers centimeter size monolayer areas where it is possible to realize a comparative analysis of different devices with nominally the same barrier. In samples with a graphene gap below 400 nm, we have found evidence of Josephson coherence in presence of an incipient Berezinskii-Kosterlitz-Thouless transition. When the magnetic field is cycled, a remarkable hysteretic collapse and revival of the Josephson supercurrent occurs. Similar hysteresis are found in granular systems and are usually justified within the Bean Critical State model (CSM). We show that the CSM, with appropriate account for the low dimensional geometry, can partly explain the odd features measured in these junctions.

13 pages, 9 figures

References in corpus (12)

• The electronic properties of graphene
• Doping graphene with metal contacts
• Andreev reflection and Klein tunneling in graphene
• Specular Andreev reflection in graphene
• Tunable Supercurrent Through Semiconductor Nanowires
• Epitaxial graphene transistors on SiC substrates
• Interaction Effects in Topological Superconducting Wires Supporting Majorana Fermions
• Transport Through Andreev Bound States in a Graphene Quantum Dot
• Spin Orbit coupling and Anomalous Josephson effect in Nanowires
• Excitation gap of a graphene channel with superconducting boundaries
• Influence of Topological Edge States on the Properties of Al/Bi2Se3/Al Hybrid Josephson Devices
• Screening Clouds and Majorana Fermions

Cited by in corpus (2)

• Hysteretic vortex matching effects in high-$T_c$ superconductors with nanoscale periodic pinning landscapes fabricated by He ion beam projection technique
• Thermal transport driven by charge imbalance in graphene in magnetic field, close to the charge neutrality point at low temperature: Non local resistance