Spontaneous emergence of Josephson junctions in homogeneous rings of single-crystal Sr₂RuO₄

This paper provides evidence of intrinsic Josephson junctions in mesoscopic rings structured from Sr₂RuO₄ single crystals, a material suggested to have a chiral *p*-wave order parameter. Transport experiments on these rings show distinct critical current oscillations with periodicity corresponding to the flux quantum, indicative of Josephson junctions. These oscillations are absent in rings exhibiting a broader superconducting transition, suggesting a link to the chiral nature of the superconductivity. Order parameter simulations support the existence of stable domain walls within the rings, acting as intrinsic Josephson junctions.

Yuuki Yasui, Kaveh Lahabi, Victor Fernández Becerra, Remko Fermin, Muhammad Shahbaz Anwar, Shingo Yonezawa, Takahito Terashima, Milorad V. Milošević, Jan Aarts, Yoshiteru Maeno