Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 43: Poster Tuesday: Electronic Structure

O 43.4: Poster

Dienstag, 2. April 2019, 18:00–20:00, Poster D

On superconducting properties of clean Nb(110) surface and its magnetic adatom-induced Yu-Shiba-Rusinov states — •Artem B. Odobesko, Stefan Wilfert, Robin Boshuis, and Matthias Bode — Physikalisches Institut, Universität Würzburg, Am Hubland, Würzburg, Germany

We have studied cleaning procedures of Nb(110) by low-energy electron diffraction, Auger electron spectroscopy, and scanning tunneling microscopy and spectroscopy. Our results show that the formation of a surface-near impurity depletion zone is inhibited by the very high diffusivity of oxygen in the Nb host crystal. Oxygen can be removed from the surface by heating the crystal to T ∼ 2400^∘C. Tunneling spectra measured on the clean Nb(110) surface exhibit a sharp conductance peak in the occupied states at an energy of about -450 meV. The clean Nb(110) surface is superconducting with a gap width and a critical magnetic field strength in good agreement to the bulk value. Spatially resolved spectra take in an external magnetic field show a zero-bias anomaly in the vortex core. We will discuss the potential of the Nb(110) surface to serve as a platform for Yu-Shiba-Rusinov bound states inside the superconducting gap when magnetic impurities induce a pair-breaking scattering potential for Cooper pairs [1]. The adsorption site–dependence of the Yu-Shiba-Rusinov states will be explored by atomic manipulation.

[1] B.W. Heinrich, J.I. Pascual, K.J. Franke, Prog. Surf. Sci. textbf93, 1 (2018).