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MI: Fachverband Mikrosonden

MI 4: Scanning Probe Microscopy

MI 4.1: Vortrag

Dienstag, 1. April 2014, 11:15–11:30, MER 02

Towards the measurement of atomic-scale forces associated with a superconducting transition — •Angelo Peronio and Franz J. Giessibl — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany

The superconducting phase transition alters the electron energy spectrum of a metal, opening up a gap in the density of electronic states around the Fermi energy. The width of this is gap few meV at most, reflecting the strength of the interaction that binds the electrons in superconducting Cooper pairs. This modification of the electronic spectrum, albeit slight, is sufficient to reduce the friction of a niobium surface by a factor of 3 across the superconducting transition temperature [1].

Driven by this evidence, we will present an attempt to detect atomic-scale forces associated with the superconducting transition. In particular, we investigated a well-defined test system with a qPlus AFM sensor [2] equipped with a niobium tip, in order to map the interaction potential between the tip apex and the sample.

References:

[1] Kisiel et al., Nat. Mater. 10 (2011) 119

http://dx.doi.org/10.1038/nmat2936

[2] Giessibl, Appl. Phys. Lett. 73 (1998) 3956

http://dx.doi.org/10.1063/1.122948