Christoph Strunk | Supercurrent diode effects and ‘0-instabilities in synthetic Rashba Josephson junctions

Christoph Strunk, Institute of Experimental and Applied Physics, University of Regensburg, Germany

We study Josephson junctions in epitaxial Al/InGaAs/InAs heterostructures. Using
reflectometry, we measure the Josephson inductance as well as DC transport properties.
We nd that our junctions are in the ballistic limit, featuring a current phase relation
with near-unity transmission [1]. When applying in-plane magnetic eld perpendicular to
the current, the Josephson inductance reveals the presence of non-reciprocal supercurrent
far below the superconducting transition temperature that results from magnetochiral
anisotropy. Also the transport critical current Ic displays a pronounced superconducting
diode eect [2]. As the result of a small Dresselhaus component, the orientation of the
current with respect to the lattice aects the magnetochiral anisotropy [3]. At higher
magnetic eld the coecient of magneto-chiral anisotropy changes sign. This can be
understood as an instability of the spontaneous ‘0-shift, resulting from competing ground
states in the Josephson coupling energy.

[1] C. Baumgartner et al., Phys. Rev. Lett. 126, 037001 (2021).
[2] C. Baumgartner et al., Nature Nanotechnology 17, 39 (2022).
[3] C. Baumgartner et al., J. Phys. Condens. Matter 34, 154005 (2022).