Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 16: Superconductivity: Properties and Electronic Structure II
TT 16.6: Vortrag
Montag, 12. März 2018, 16:30–16:45, H 0110
Experimental test of an alternative electrodynamic theory of superconductors by means of scanning tunnelling and force microscopy — Sungmin Kim1,4, Johannes Schwenk1,2, Julian Berwanger3, •Angelo Peronio3, Steven R. Blankenship1, William G. Cullen1, Young Kuk4, Franz J. Giessibl3, and Joseph A. Stroscio1 — 1NIST, Gaithersburg, Maryland — 2University of Maryland, College Park, Maryland — 3University of Regensburg, Germany — 4Seoul National University, Korea
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.
If a superconductor screens electric fields differently from a normal metal, the electrostatic interaction between a scanning probe tip and a superconductive sample should change when the latter becomes superconductive. We report on experiments to test Hirsch’s hypothesis, performed on aluminium samples in a combined STM/AFM microscope operated in ultra-high vacuum at mK temperatures.
F. London, Superfluids Vol. I, Wiley (1950)
J. E. Hirsch, Physica C 508, 21 (2015)