Novel 0–π transitions in Josephson junctions between noncentrosymmetric superconductors∗

We study the Josephson effect between two noncentrosymmetric superconductors (NCSs) with opposite polarization vectors of Rashba spin–orbit coupling (RSOC). We find a 0–π transition driven by the triplet–singlet ratio of NCSs. Different from conventional 0–π transitions, the Andreev bound states change their energy range instead of phase shift in the 0–π transition found here. This novel property results in a feature that the critical current becomes almost zero at the transition point, not only a minimum. Furthermore, when the directions of RSOC polarization vectors are the same in two NCSs, the similar effect can also be found in the presence of a perpendicular exchange field or a Dresselhause spin–orbit coupling in the interlayer. We find novel oscillations of critical current without 0–π transition. These novel 0–π transitions or oscillations of critical current present new understanding of the Josephson effect and can also serve as a tool to determine the unknown triplet–singlet ratio of NCSs.