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TT: Fachverband Tiefe Temperaturen

TT 3: Superconductivity: Properties and Electronic Structure I

TT 3.3: Talk

Monday, March 12, 2018, 10:00–10:15, H 0110

Nonequilibrium transport in ultrathin aluminium films near the vortex-unbinding transition — •Klaus Kronfeldner, Lorenz Fuchs, and Christoph Strunk — Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany

We analyze I(V)-characteristics and ac-susceptibility of epitaxial aluminium films with thicknesses below 8 nm. The Berezinskii-Kosterlitz-Thouless transition temperature T_BKT is determined from the superfluid stiffnesses that are extracted from both measurement techniques. For the dc-measurement the power-law criterion with slope 3 in log(V) vs. log(I) is used to determine T_BKT. While the two independently identified values for T_BKT are in good agreement for the lowest voltages V, at higher V a pronounced concave curvature is visible in the log(V) vs. log(I) plot. This curvature is traced back to both changes in the superfluid stiffness and self-heating in presence of a driving current.