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

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.

Authors:
; ; ; ;  [1];  [1];  [2]
  1. Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Saale) (Germany)
  2. (Saale) (Germany)
Publication Date:
OSTI Identifier:
22454426
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 1; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DENSITY OF STATES; FILMS; ISLANDS; LAYERS; MEV RANGE; PROXIMITY EFFECT; SCANNING TUNNELING MICROSCOPY; SPECTROSCOPY; SUPERCONDUCTIVITY; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE; TUNNEL EFFECT

Citation Formats

Stępniak, A., Caminale, M., Leon Vanegas, A. A., Oka, H., Sander, D., E-mail: sander@mpi-halle.mpg.de, Kirschner, J., and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle. Temperature dependence of the superconducting proximity effect quantified by scanning tunneling spectroscopy. United States: N. p., 2015. Web. doi:10.1063/1.4906554.
Stępniak, A., Caminale, M., Leon Vanegas, A. A., Oka, H., Sander, D., E-mail: sander@mpi-halle.mpg.de, Kirschner, J., & Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle. Temperature dependence of the superconducting proximity effect quantified by scanning tunneling spectroscopy. United States. doi:10.1063/1.4906554.
Stępniak, A., Caminale, M., Leon Vanegas, A. A., Oka, H., Sander, D., E-mail: sander@mpi-halle.mpg.de, Kirschner, J., and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle. Thu . "Temperature dependence of the superconducting proximity effect quantified by scanning tunneling spectroscopy". United States. doi:10.1063/1.4906554.
@article{osti_22454426,
title = {Temperature dependence of the superconducting proximity effect quantified by scanning tunneling spectroscopy},
author = {Stępniak, A. and Caminale, M. and Leon Vanegas, A. A. and Oka, H. and Sander, D., E-mail: sander@mpi-halle.mpg.de and Kirschner, J. and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle},
abstractNote = {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.},
doi = {10.1063/1.4906554},
journal = {AIP Advances},
number = 1,
volume = 5,
place = {United States},
year = {Thu Jan 15 00:00:00 EST 2015},
month = {Thu Jan 15 00:00:00 EST 2015}
}