Regensburg 2022 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 30: Superconductivity: Poster Session

TT 30.14: Poster

Thursday, September 8, 2022, 15:00–18:00, P1

Interplay between charging effects and superconducting transport in a tunable SET — •David Christian Ohnmacht¹, Laura Sobral Rey¹, Jens Siewert², Wolfgang Belzig¹, and Elke Scheer¹ — ¹Universität Konstanz, Konstanz, Deutschland — ²University of the Basque Country, Bilbao, Spain

All-superconducting single electron transistors (SSS-SETs) have shown to enable a multitude of possible charge transport processes which are not well understood, in particular in the strong-coupling regime [1]. To disentangle these processes, the conceptually simpler (SSN)-SET, which has never been investigated experimentally before is considered [2]. Electron tunneling, Cooper pair tunneling and (multiple) Andreev reflection ((M)AR) are possible in the S-S mechanically controlled break junction (MCBJ) which can be adjusted to cover all coupling regimes: from a tunnel contact to a point contact with a small number of highly transmissive transport channels. The experimental data is compared to theoretical results obtained by using a master equation approach, including the rates of different transport mechanisms [3]. In order to account for MAR, we include the rates for the individual processes which are obtained from the theory of full counting statistics into the master equation framework [4]. The rates for MAR are computed using transmission probabilities according to the experimental data taking into account the presence of multiple transport channels. The limits of this master equation approach for a SSN-SET with a MCBJ are discussed in detail. Finally, it is shown that the charging energy decreases as the coupling of the MCBJ increases.