Superconducting diode effect and interference patterns in kagome CsV₃Sb₅.

Abstract

The interplay among frustrated lattice geometry, non-trivial band topology and correlation yields rich quantum states of matter in kagome systems^1,2. A series of recent members in this family, AV₃Sb₅ (A = K, Rb or Cs), exhibit a cascade of symmetry-breaking transitions³, involving the 3Q chiral charge ordering^4-8, electronic nematicity^9,10, roton pair density wave¹¹ and superconductivity¹². The nature of the superconducting order is yet to be resolved. Here we report an indication of dynamic superconducting domains with boundary supercurrents in intrinsic CsV₃Sb₅ flakes. The magnetic field-free superconducting diode effect is observed with polarity modulated by thermal histories, suggesting that there are dynamic superconducting order domains in a spontaneous time-reversal symmetry-breaking background. Strikingly, the critical current exhibits double-slit superconductivity interference patterns when subjected to an external magnetic field. The characteristics of the patterns are modulated by thermal cycling. These phenomena are proposed as a consequence of periodically modulated supercurrents flowing along certain domain boundaries constrained by fluxoid quantization. Our results imply a time-reversal symmetry-breaking superconducting order, opening a potential for exploring exotic physics, for example, Majorana zero modes, in this intriguing topological kagome system.