Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 14: Superconductivity: (General) Theory

TT 14.4: Vortrag

Montag, 7. März 2016, 15:45–16:00, H19

Utilizing atomic force spectroscopy to test an alternative electrodynamic theory of superconductors — •Angelo Peronio and Franz J. Giessibl — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany

In the traditional theoretical description of superconductivity, a static electric field cannot penetrate a superconductor, since screening occurs like in a normal metal. This can be traced back to the fact that the London equations [1], the phenomenological equations describing the electrodynamics of superconductors, are derived within the Coulomb gauge. J. E. Hirsch proposes to use the Lorenz gauge instead [2], deriving a consistent solution where the electric field penetrates the superconductor up to the London penetration depth.

We report on initial experiments to test Hirsch’s hypothesis, performed with a combined STM/AFM qPlus sensor equipped with a superconducting tip. If a superconductor screens electric fields differently from a normal metal, the electrostatic interaction between tip and sample should change when the tip becomes superconductive.

[1] F. London, Superfluids Vol. I, Wiley (1950)

[2] J. E. Hirsch, Physica C 508, 21 (2015)