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arXiv · 1809.09376

Tunneling spectroscopy of graphene nanodevices coupled to large-gap superconductors

Joel I-Jan Wang·Landry Bretheau·Daniel Rodan-Legrain·Riccardo Pisoni·Kenji Watanabe·Takashi Taniguchi·Pablo Jarillo-Herrero
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Abstract

We performed tunneling spectroscopy measurements of graphene coupled to niobium/niobium-nitride superconducting electrodes. Due to the proximity effect, the graphene density of states depends on the phase difference between the superconductors and exhibits a hard induced gap at zero phase, consistent with a continuum of Andreev bound states. At energies larger than the superconducting gap, we observed phase-dependent energy levels displaying the Coulomb blockade effect, which are interpreted as arising from spurious quantum dots, presumably embedded in the heterostructures and coupled to the proximitized graphene.

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Joel I-Jan Wang, Landry Bretheau, Daniel Rodan-Legrain, Riccardo Pisoni, Kenji Watanabe, Takashi Taniguchi, Pablo Jarillo-Herrero. 2018-09-25. Tunneling spectroscopy of graphene nanodevices coupled to large-gap superconductors. https://doi.org/10.1103/physrevb.98.121411

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