Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Superconductivity: Tunnelling and Josephson Junctions I

TT 6.8: Hauptvortrag

Montag, 18. März 2024, 11:30–12:00, H 3010

Theory of supercurrent diode effect and other spin-orbit-driven phenomena in superconducting magnetic junctions — •Andreas Costa — University of Regensburg, Germany

Their extraordinary physical properties to tailor spin-polarized triplet supercurrents—exploiting, e.g., spin-orbit coupling (SOC)—make superconducting magnetic junctions a promising platform to implement quantum-computing concepts or explore topological effects.

The first part of this talk will give a more general overview of such junctions’ SOC-driven transport anomalies, covering giant transport magnetoanisotropies that result from the triplet-current-inducing unconventional (spin-flip) Andreev-reflection process [1,2] and sizable transverse Hall supercurrents that originate from SOC-induced skew scattering of charge carriers [3].

In the second part of the talk, we will focus on our theoretical model developed to understand the supercurrent diode effect (SDE) in Al/InAs-based Josephson-junction arrays [4–6]. The competition between SOC and an appropriately aligned magnetic field imprints a strong polarity dependence on the critical Josephson currents with characteristic features, such as 0–π-like transitions and a possible reversal of the SDE, that we could further characterize with our model.

This work has been supported by DFG Grants 454646522 and 314695032 (SFB 1277), and by ENB IDK Topological Insulators.

1] Phys. Rev. Lett. 115 (2015) 116601

[2] Phys. Rev. B 95 (2017) 024514

[3] Phys. Rev. B 100 (2020) 060507(R)

[4] Nat. Nanotechnol. 17(2022)39

[5] Nat. Nanotechnol. 18 (2023) 1266

[6] Phys. Rev. B 108 (2023) 054522

Keywords: Josephson junctions; Andreev reflection; supercurrent diode effect