Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Electronic Structure of Surfaces II
O 58.1: Vortrag
Mittwoch, 18. März 2015, 15:00–15:15, MA 041
Two-band superconductivity of lead probed by scanning tunneling spectroscopy — •Michael Ruby1, Benjamin W. Heinrich1, Jose I. Pascual2, and Katharina J. Franke1 — 1Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 2CIC nanoGUNE and Ikerbasque, Basque Foundation for Science, Tolosa Hiribidea 78, Donostia-San Sebastian 20018, Spain
The type I superconductor lead (Pb) has been theoretically predicted to be a two-band superconductor [1]. We use scanning tunneling spectroscopy to resolve two superconducting gaps
with an energy difference of 130 µeV.
Tunneling into Pb(111), Pb(110) and Pb(100) crystals reveals a strong dependence of the
two coherence peak intensities on the crystal orientation.
We show that this is the result of a selective tunneling into
the two bands at the energy of the two coherence peaks.
This is further sustained by the observation of signatures of the Fermi sheets
in differential conductance maps around subsurface defects.
A. Floris et al., Phys. Rev. B 75, 054508, (2007)