Enhanced Andreev reflection in gapped graphene

Abstract

We theoretically demonstrate unusual features of superconducting proximity effect in gapped graphene which presents a pseudospin symmetry-broken ferromagnet with a net pseudomagnetization. We find that the presence of a band gap makes the Andreev conductance of graphene superconductor/pseudoferromagnet (S/PF) junction to behave similar to that of a graphene ferromagnet-superconductor junction. The energy gap ${\Delta }_N$ enhance the pseudospin inverted Andreev conductance of S/PF junction to reach a limiting maximum value for ${\Delta }_N\gg \mu$, which depending on the bias voltage can be larger than the value for the corresponding junction with no energy gap. We further demonstrate a damped-oscillatory behavior for the local density of states of the PF region of S/PF junction and a long-range crossed Andreev reflection process in PF/S/PF structure with antiparallel alignment of pseudomagnetizations of PFs, which confirm that, in this respect, the gapped normal graphene behaves like a ferromagnetic graphene.

7.2 pages, 5 figures, accepted for publication in Phys. Rev. B

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Cited by in corpus (12)

• Valley- and spin-switch effects in molybdenum disulfide superconducting spin valve
• Electrical control of crossed Andreev reflection and spin-valley switch in antiferromagnet/superconductor junctions
• Andreev reflection in monolayer MoS2
• Enhanced Specular Andreev reflection in bilayer graphene
• The influence of anti-chiral edge states on Andreev reflection in graphene-superconductor junction
• Spin-valley dependent double Andreev reflections in the proximitized graphene/superconductor junction
• Pseudo-spin triplet superconductivity in transition-metal dichalcogenide monolayers and Andreev reflection in the lateral heterostructures of 2$H$-NbSe${}_2$
• Andreev tunnelling and Josephson current in light irradiated graphene
• Andreev and normal reflections in gapped bilayer graphene-superconductor junctions
• New supercurrent pattern in quantum point contact with strained graphene nanoribbon
• Electrical and thermal transport in a twisted heterostructure of transition metal dichalcogenide and CrI${}_3$ connected to a superconductor
• Transport through Nodal Surface Semimetal-Superconductor junction in absence/presence of light irradiation