Anomalous Josephson Effects from Spin-Orbit Interaction in Ballistic Josephson Junctions

SPICE Workshop on Hybrid Correlated States and Dynamics in Quantum Materials, May 14th - 16th 2024

Christoph Strunk

Universität Regensburg, Germany

The recent discovery of intrinsic supercurrent diode effect [1], and its prompt observation in a rich variety of systems, has shown that nonreciprocal supercurrents naturally emerge when both space- and time-inversion symmetries are broken. I will report on both dc and ac-
manifestations of the Josephson diode effect in the non-linear inductance in
planar Josephson junctions, based on a ballistic Al/InAs-heterostructure that is exposed to
an in-plane magnetic field Bip [2].
At low Bip a non-reciprocal term is found in the inductance that is linear in Bip. At higher Bip a sign reversal of the magnetochiral term is observed that can be traced back to a 0--like
transition in the current-phase relation [3]. Different avenues for a theoretical interpretation
are discussed. As pronounced date tunability of both the 0 shift and the diode efficiency in
an asymmetric SQUID device demonstrates that Rashba spin-orbit interaction provides a
substantial contribution to the Josephson diode effect [4].

[1] F. Ando et al., Nature 584, 373 (2020).
[2] C. Baumgartner et al., Nature Nanotech. 17, 39 (2022).
[3] C. Baumgartner et al., Nature Nanotech. (2023).
[4] S. Reinhardt et al., arXiv.2308.01061