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TT 55.7: Vortrag
Donnerstag, 19. März 2020, 11:30–11:45, HSZ 204
Josephson and Andreev transport in a superconducting single electron transistor with a normal lead (SSN SET) — •Laura Sobral Rey1,2, Susanne Sprenger1, and Elke Scheer1,2 — 1Physics department, University of Konstanz, 78464, Konstanz, Germany — 2QuESTech consortium
An island coupled via a tunnel barrier to two leads and a gate forms a single electron transistor (SET) that shows Coulomb blockade. All-superconducting SETs (SSS-SETs) have shown to enable multitude of possible charge transport processes which are not well understood, in particular in the strong-coupling regime . To disentangle these processes, we study here the conceptually simpler SSN-SET, which has never been investigated experimentally before.
The SSN-SETs studied here consist of an S island coupled to an N lead via an oxide tunnel barrier, and to an S lead with a mechanically controlled break junction (MCBJ). Via the MCBJ, different coupling regimes can be tuned: from a tunnel contact when the MCBJ is broken to a point contact when it is closed. In that limit the MCBJ accommodates a small number of highly transmissive transport channels.
For weak coupling our experimental findings can be understood in terms of the orthodox theory . For stronger couplings, we observe Andreev and Josephson transport, as well as a renormalization for the charging energy and dynamical coulomb blockade, which are also observed in the N state.
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