Josephson coupling between superconducting islands on single- and bi-layer graphene
Number of Authors: 3
2016 (English)In: Superconductors Science and Technology, ISSN 0953-2048, E-ISSN 1361-6668, Vol. 29, no 5, 054004Article in journal (Refereed) Published
We study the Josephson coupling of superconducting (SC) islands through the surface of single-layer graphene (SLG) and bilayer graphene (BLG) in the long-junction regime, as a function of the distance between the grains, temperature, chemical potential and external (transverse) gate-voltage. For SLG, we provide a comparison with existing literature. The proximity effect is analyzed through a Matsubara Green's function approach. This represents the first step in a discussion of the conditions for the onset of a granular superconductivity within the film, made possible by Josephson currents flowing between superconductors. To ensure phase coherence over the 2D sample, a random spatial distribution can be assumed for the SC islands on the SLG sheet (or intercalating the BLG sheets). The tunable gate-voltage-induced band gap of BLG affects the asymptotic decay of the Josephson coupling-distance characteristic for each pair of SC islands in the sample, which results in a qualitatively strong field dependence of the relation between Berezinskii-Kosterlitz-Thouless transition critical temperature and gate voltage.
Place, publisher, year, edition, pages
2016. Vol. 29, no 5, 054004
graphene, bilayer graphene, Josephson coupling, supercurrent, long-junction regime
IdentifiersURN: urn:nbn:se:su:diva-131220DOI: 10.1088/0953-2048/29/5/054004ISI: 000375572100007OAI: oai:DiVA.org:su-131220DiVA: diva2:936716