Superconducting proximity effect in graphene under inhomogeneous strain

Abstract

The interplay between quantum Hall states and Cooper pairs is usually hindered by the suppression of the superconducting state due to the strong magnetic fields needed to observe the quantum Hall effect. From this point of view graphene is special since it allows the creation of strong pseudo-magnetic fields due to strain. We show that in a Josephson junction made of strained graphene, Cooper pairs will diffuse into the strained region. The pair correlation function will be sub-lattice polarized due to the polarization of the local density of states in the zero pseudo-Landau level. We uncover two regimes; 1) one in which the cyclotron radius is larger than the junction length in which case the supercurrent will be enhanced, and 2) the long junction regime where the supercurrent is strongly suppressed because the junction becomes an insulator. In the latter case quantized Hall states form and Andreev scattering at the normal/superconducting interface will induce edge states. Our numerical calculation has become possible due to an extension of the Chebyshev Bogoliubov-de Gennes method to computations on video cards (GPUs).

to appear in PRB

References in corpus (13)

• The electronic properties of graphene
• A tight-binding approach to uniaxial strain in graphene
• Andreev reflection and Klein tunneling in graphene
• Bipolar supercurrent in graphene
• The Kernel Polynomial Method
• Midgap states and charge inhomogeneities in corrugated graphene
• Josephson effect in ballistic graphene
• Pseudomagnetic fields and ballistic transport in a suspended graphene sheet
• Wave packet dynamics and valley filter in strained graphene
• Chebyshev-BdG: an efficient numerical approach to inhomogeneous superconductivity
• Andreev reflection at high magnetic fields: Evidence for electron and hole transport in edge states
• Andreev reflection and cyclotron motion at superconductor -- normal-metal interfaces
• Tunable Supercurrent at the Charge Neutrality Point via Strained Graphene Junctions

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• Tight-binding description of intrinsic superconducting correlations in multilayer graphene
• Unconventional vortex states in nanoscale superconductors due to shape-induced resonances in the inhomogeneous Cooper-pair condensate
• Vortex states in nanoscale superconducting squares: the influence of quantum confinement
• Pseudo-Landau levels of Bogoliubov quasiparticles in strained nodal superconductors
• Strain Controlled Spin and Charge Pumping in Graphene Devices via Spin-orbit Coupled Barriers
• Magnetic field oscillations of the critical current in long ballistic graphene Josephson junctions
• Tight-binding study of bilayer graphene Josephson junctions
• Probing unconventional superconductivity in proximitized graphene by impurity scattering
• Inhomogeneous superconductivity in the presence of time-reversal symmetry
• Disordered graphene Josephson junctions
• Andreev reflection in edge states of time reversal invariant Landau levels
• Superconducting current and proximity effect in ABA and ABC multilayer graphene Josephson junctions
• Anomalous quantum interference effects in graphene SNS junctions due to strain-induced gauge fields
• Dynamical heterogeneities as fingerprints of a backbone structure in Potts models
• Helical superconducting edge modes from pseudo-Landau levels in graphene
• New supercurrent pattern in quantum point contact with strained graphene nanoribbon
• Topological Superfluid Responses of Superconducting Dirac Semimetals
• Superfluid Stiffness and Josephson Quantum Capacitance: Adiabatic Approach and Topological Effects