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arXiv · 1702.03686

Closing the superconducting gap in small Pb-nanoislands with high magnetic fields

Steffen Rolf-Pissarczyk·Jacob A. J. Burgess·Shichao Yan·Sebastian Loth
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Abstract

Superconducting properties change in confined geometries. Here we study the effects of strong confinement in nanosized Pb-islands on Si(111) 7x7. Small hexagonal islands with diameters less than 50 nm and a uniform height of 7 atomic layers are formed by depositing Pb at low temperature and annealing at 300 K. We measure the tunneling spectra of individual Pb-nanoislands using a low-temperature scanning tunneling microscope operated at 0.6 K, and follow the narrowing of the superconducting gap as a function of magnetic field. We find the critical magnetic field, at which the superconducting gap vanishes, reaches several Tesla, which represents a greater than 50-fold enhancement compared to the bulk value. By independently measuring the size of the superconducting gap, and the critical magnetic field that quenches superconductivity for a range of nanoislands we can correlate these two fundamental parameters and estimate the maximal achievable critical field for 7 ML Pb-nanoislands to 7 T.

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Steffen Rolf-Pissarczyk, Jacob A. J. Burgess, Shichao Yan, Sebastian Loth. 2017-02-13. Closing the superconducting gap in small Pb-nanoislands with high magnetic fields. https://doi.org/10.1103/physrevb.94.224504

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