Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 16: Scanning probe methods I

O 16.8: Talk

Monday, March 14, 2011, 16:45–17:00, WIL C307

Low Temperature Scanning Tunneling Spectroscopy on high quality Nb(110) films — •Matthias Stocker, Holger Pfeifer, Berndt Koslowski, and Paul Ziemann — Institut für Festkörperphysik, Universität Ulm, D-89069 Ulm, Germany

High quality Nb(110) films were prepared by evaporation onto (0001)oriented sapphire substrates at 850^∘C and analyzed in situ by Low Temperature Scanning Tunneling Spectroscopy (LT-STS). In this way, the superconducting gap in the quasi-particle density of states (DOS) of Nb(110) is investigated. The incomplete opening of this gap at 5.3 K can be attributed to the somewhat higher tip temperature of ∼ 7 K. Significant structures in the I-V data positioned symmetrically around zero energy and matching nicely known phonon energies of Nb indicate strong coupling behavior of this superconductor. These results suggest attempting an evaluation of the corresponding Eliashberg function, α² F(ω).