We study Josephson junctions based on InSb nanowires with Sn shells. We observe skewed critical current diffraction patterns: the maxima in forward and reverse current bias are at different magnetic flux, with a displacement of 20-40 mT. The skew is greatest when the external field is nearly perpendicular to the nanowire, in the substrate plane. This orientation suggests that spin-orbit interaction plays a role. We develop a phenomenological model and perform tight-binding calculations, both methods reproducing the essential features of the experiment. The effect modeled is the ϕ0-Josephson junction with higher-order Josephson harmonics. The system is of interest for Majorana studies: the effects are either precursor to or concomitant with topological superconductivity. Current-phase relations that lack inversion symmetry can also be used to design quantum circuits with engineered nonlinearity.
@article{arxiv.2212.00199,
title = {Evidence of $\phi$0-Josephson junction from skewed diffraction patterns in Sn-InSb nanowires},
author = {B. Zhang and Z. Li and V. Aguilar and P. Zhang and M. Pendharkar and C. Dempsey and J. S. Lee and S. D. Harrington and S. Tan and J. S. Meyer and M. Houzet and C. J. Palmstrom and S. M. Frolov},
journal= {arXiv preprint arXiv:2212.00199},
year = {2025}
}