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Abstract: The interplay between Rashba spin-orbit interaction and Zeeman fields gives rise to the anomalous Josephson effect: An anomalous phase-shift φ0 in the junctions current-phase relation. We measure the φ0-shift via a kinked junction geometry realized in a weak link realized in an epitaxial Al/InAs heterostructure. An intentional variation of φ0 along the weak link is introduced by its angle with respect to an in-plane magnetic field. This results in a unique quantum interference pattern, from which the corresponding φ0-shift is extracted with the help of a minimal theoretical model. When the rotating the magnetic field in plane, the φ0-shift and the supercurrent diode effect alternate in magnitude. In a second experiment we measure the current-phase relation of a Josephson junction in a HgTe 3D topological insulator weak link. The Josephson current through the topological surface states is dominant, and gives rise to a strongly anharmonic current phase relation. In the presence of an in-plane magnetic field, we measure a giant φ0-shift that is about 50 times larger than in InAs. The magnitude of the effect is attributed to the presence of only a single Fermi contour in the topological surface states. Rotating the magnetic field in the plane reveals a nearly isotropic spin texture with maximum φ0-shift at 109° with respect to the current direction. In addition to a Rashba term, this suggests the contribution of a Weyl-like contribution to the spin-orbit coupling, which favours a parallel alignment of spin and momentum and is consistent with the (013)-orientation of the HgTe surface.
