Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 72: Low-Dimensional Systems: Poster Session
TT 72.5: Poster
Wednesday, March 18, 2015, 15:00–18:00, Poster B
Superconductivity at the interface of SrTiO3 and amorphous Al2O3 — •Roland Schäfer1, Dirk Fuchs1, Ahmed Sleem1, Rudolf Schneider1, Richard Thelen2, and Hilbert von Löhneysen1,3 — 1Karlsruher Institut für Technologie, Institut für Festkörperphysik, 76021 Karlsruhe — 2Karlsruher Institut für Technologie, Institut für Mikrostrukturtechnik, 76021 Karlsruhe — 3Karlsruher Institut für Technologie, Physikalisches Institut, 76131 Karlsruhe
We investigate the two-dimensional (2D) electron gas forming at the interface of TiO2 terminated SrTiO3 and amorphous Al2O3. The resistance drops on cooling from room temperature down to 200 mK in an usual way by a factor of up to 250. Below 200 mK the system becomes superconducting. We investigate the superconducting phase transition by analyzing voltage vs. current (V/I) characteristics as a function of temperature and magnetic field. The I/V characteristics show a power law scaling V∝Iα at low bias with a temperature dependent exponent α which is close to 1 at high temperatures rises to 3 at around T≈160 mK and rapidly ascents on further lowering the temperature. This behaviour is typical for a Berezinskii-Kosterlitz-Thouless transistion found in 2D superconductive layers.