Temperature dependence of the superconducting proximity effect quantified by scanning tunneling spectroscopy

A. Stępniak, M. Caminale, A. A. Leon Vanegas, H. Oka, D. Sander, J. Kirschner

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8 Citations (Scopus)

Abstract

Here, we present the first systematic study on the temperature dependence of the extension of the superconducting proximity effect in a 1-2 atomic layer thin metallic film, surrounding a superconducting Pb island. Scanning tunneling microscopy/spectroscopy (STM/STS) measurements reveal the spatial variation of the local density of state on the film from 0.38 up to 1.8 K. In this temperature range the superconductivity of the island is almost unaffected and shows a constant gap of a 1.20 ± 0.03 meV. Using a superconducting Nb-tip a constant value of the proximity length of 17 ± 3 nm at 0.38 and 1.8 K is found. In contrast, experiments with a normal conductive W-tip indicate an apparent decrease of the proximity length with increasing temperature. This result is ascribed to the thermal broadening of the occupation of states of the tip, and it does not reflect an intrinsic temperature dependence of the proximity length. Our tunneling spectroscopy experiments shed fresh light on the fundamental issue of the temperature dependence of the proximity effect for atomic monolayers, where the intrinsic temperature dependence of the proximity effect is comparably weak.

Original languageEnglish
Article number017125
JournalAIP Advances
Volume5
Issue number1
DOIs
Publication statusPublished - 2015 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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