Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 49: Poster Session: Superconductivity

TT 49.27: Poster

Mittwoch, 3. April 2019, 15:00–18:30, Poster D

Coulomb blockade experiments beyond orthodox theory — •Laura Sobral Rey, Susanne Sprenger, and Elke Scheer — Universität Konstanz, 78467 Konstanz, Deutschland

A single electron transistor (SET) can be built by connecting a island with two tunnel junctions to their respective leads and a gate electrode. Previous works were focused on studying all superconducting SET (SSS) [1] or a normal island with superconducting leads (SNS)[2]. The contributions to the current through these devices (related to Coulomb blockade (CB)) are quantitatively covered by the orthodox theory in this weak-coupling regime. The strong-coupling regime can be studied by replacing one tunnel junction by a mechanically controlled break junction (MCBJ) [3]. In this regime, in a SSS SET, new effects not covered by the orthodox theory appear, like for instance multiple Andreev reflection (MAR).

To further investigate the non-orthodox Josephson quasiparticle cycle we design a SSN SET to suppress the Josephson coupling of the island to one of the leads. This should be done by using Cu lead connected to the island by a CuO_x barrier. All the coupling regimes can be addressed by opening or closing the MCBJ: MAR is expected when it’s closed and tunnelling transport when it’s broken.
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