Simon Reinhardt

Institut für Experimentelle und Angewandte Physik, University of Regensburg, 93040 Regensburg, Germany

Non-reciprocal effects in ballistic superconductor/semiconductor Josephson junctions

Since the discovery of the supercurrent diode effect by Ando et al. [1] and its observation in a rich variety of systems, there is an increasing interest in the physics of non-reciprocal superconductivity. In this talk I will present recent results on non-reciprocal phenomena in hybrid aluminum/InGaAs/InAs Josephson junction devices. In the first part of the talk, I will show how spin-orbit interaction in combination with a Zeeman field leads to a non-reciprocal Josephson inductance and supercurrent diode effect [2,3,4]. Using a superconducting quantum interferometer we simultaneously measure φ₀-shift and supercurrent diode effect on a single junction [5]. By electrostatic gating of the junction, we reveal the link between φ₀-shift and supercurrent diode effect. In the second part of the talk, I will present recent work on two-dimensional Josephson junction arrays fabricated in super/semi heterostructures. An out-of-plane magnetic field induces vortices, which form ordered patterns for commensurate values of the frustration parameter. We probe the symmetry of the intrinsic vortex pinning potential by measuring the depinning current. When applying in-plane magnetic fields, non-reciprocal behavior of the depinning current is observed, revealing a ratchet-like pinning potential. We demonstrate how this novel effect arises from the combination of multi-terminal character of the Josephson junctions in the array with the interplay of Rashba spin-orbit coupling and Zeeman field in the weak links [6].