Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 39: Tribology
O 39.6: Talk
Wednesday, September 7, 2022, 11:45–12:00, H6
Single Asperity Sliding Friction across the Superconducting Phase Transition — Wen Wang, •Dirk Dietzel, and Andrè Schirmeisen — Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
When analyzing sliding friction, it is usually an intriguing question to identify the different dissipation mechanisms contributing to friction. Usually, a number of different channels for dissipation are considered including phonon and electron systems, plastic deformation, and crack formation. Among these, especially the role of the electron system for energy dissipation often remains elusive. In this contribution, we now present experiments single asperity sliding friction monitored during AFM-measurements on a high-Tc BSCCO-superconductor. These measurements reveal a distinct temperature dependence of friction in a temperature range between 40 K and 300 K [1]. While the overall friction decreases with temperature as predicted by models about thermally activated friction, we find a distinct friction peak at about 95K. This peak can be explained by a superposition of different energy dissipation channels, where the influence of electronic contributions vanishes when cooling below the superconducting phase transition Tc. Our experiments thereby unambiguously link electronic friction effects to the number of normal state electrons in the superconducting phase below Tc. In addition, we analyze single asperity friction of BSCCO in the proximity of step-edges, where layer-defects reveal the potential influence of the topmost-layer on electronic friction contributions. [1] Wang, Dietzel, Schirmeisen, Science Advances, eaay0165 (2020)