Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 12: Poster Session Superconductivity

TT 12.47: Poster

Montag, 11. März 2013, 15:00–19:00, Poster D

Superconductivity in Thin La Films — •Lihui Zhou, Peter Löptien, Alexander Khajetoorians, Jens Wiebe, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg, Hamburg, Germany

The issue of how thin superconducting films can get before they lose their superconductivity is of relevance for the fundamental understanding of quantum confined superconductors and for their possible technological applications in nanodevices [1,2]. Here, La islands with different thicknesses in the range of the superconducting coherence length have been grown on the W(110) surface under ultra-high vacuum conditions. Low-temperature scanning tunnelling spectroscopy using non-superconducting and superconducting tips has been applied to determine the superconducting properties, i.e. the energy gap [3] and the lifetime broadening [4] of the quasiparticles. It is found that these parameters decrease linearly with the inverse island thickness, similar to recent experiments with Pb nano-islands on Si(111) [1,2], and in agreement with the theoretical calculation including a surface-energy term in the Ginzburg-Landau free-energy of a superconductor [5].
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