Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 82: Metal Substrates II
O 82.3: Vortrag
Donnerstag, 3. April 2014, 16:30–16:45, WIL A317
Probing Two-Band Superconductivity by Scanning Tunneling Spectroscopy — •Michael Ruby1, Benjamin W. Heinrich1, Jose I. Pascual1,2, 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
Recent DFT simulations have shown that the two separated
Fermi-surfaces of the strong-coupling s-wave BCS superconductor lead (Pb)
exhibit different character in
momentum space, namely s-p- and p-d-like [1].
The two Fermi-surfaces make Pb a two-band superconductor with different
gap parameter for each band.
Using scanning tunneling spectroscopy (STS) we observe an energy difference
of the gap parameters of ≈150 µV, and different intensity
for each of the BCS resonances.
We use the high spacial resolution of STS measurements to
further investigate the influence of surface defects, adsorbates, and impurities
on the density of states of the two-band superconductor.
A. Floris et al., Phys. Rev. B 75, 054508, (2007)