English

Spontaneous superconducting diode effect in non-magnetic Nb/Ru/Sr$_2$RuO$_4$ topological junctions

Superconductivity 2023-10-19 v2 Materials Science

Abstract

Non-reciprocal electronic transport in a material occurs if both time reversal and inversion symmetries are broken. The superconducting diode effect (SDE) is an exotic manifestation of this type of behavior where the critical current for positive and negative currents are mismatched, as recently observed in some non-centrosymmetric superconductors with a magnetic field. Here, we demonstrate a SDE in non-magnetic Nb/Ru/Sr2_2RuO4_4 Josephson junctions without applying an external magnetic field. The cooling history dependence of the SDE suggests that time-reversal symmetry is intrinsically broken by the superconducting phase of Sr2_2RuO4_4. Applied magnetic fields modify the SDE dynamically by randomly changing the sign of the non-reciprocity. We propose a model for such a topological junction with a conventional superconductor surrounded by a chiral superconductor with broken time reversal symmetry.

Keywords

Cite

@article{arxiv.2211.14626,
  title  = {Spontaneous superconducting diode effect in non-magnetic Nb/Ru/Sr$_2$RuO$_4$ topological junctions},
  author = {M. S. Anwar and T. Nakamura and R. Ishiguro and S. Arif and J. W. A. Robinson and S. Yonezawa and M. Sigrist and Y. Maeno},
  journal= {arXiv preprint arXiv:2211.14626},
  year   = {2023}
}