One of the consequences of Cooper pairs having a finite momentum in the interlayer of a Josephson junction, is π-junction behavior. The finite momentum can either be due to an exchange field in ferromagnetic Josephson junctions, or due to the Zeeman effect. Here, we report the observation of Zeeman effect induced 0-π transitions in Bi1−xSbx, 3D Dirac semimetal-based Josephson junctions. The large g-factor of the Zeeman effect from a magnetic field applied in the plane of the junction allows tuning of the Josephson junctions from 0- to π- regimes. This is revealed by sign changes in the modulation of the critical current by applied magnetic field of an asymmetric superconducting quantum interference device (SQUID). Additionally, we directly measure a non-sinusoidal current-phase relation in the asymmetric SQUID, consistent with models for ballistic Josephson transport.
@article{arxiv.1807.07725,
title = {Zeeman effect induced 0-$\pi$ transitions in ballistic Dirac semimetal Josephson junctions},
author = {Chuan Li and Bob de Ronde and Jorrit de Boer and Joost Ridderbos and Floris Zwanenburg and Yingkai Huang and Alexander Golubov and Alexander Brinkman},
journal= {arXiv preprint arXiv:1807.07725},
year = {2019}
}