Superconducting diode effect and interference patterns in Kagome CsV3Sb5

TL;DR

This paper reports the discovery of a magnetic field-free superconducting diode effect and interference patterns in CsV3Sb5, indicating chiral superconductivity and domain dynamics in a topological Kagome system.

Contribution

It provides evidence of chiral superconducting domains and boundary supercurrents, revealing novel quantum phenomena in Kagome CsV3Sb5.

Findings

Superconducting diode effect modulated by thermal history

Observation of double-slit interference patterns under magnetic field

Indications of chiral superconducting order and domain boundaries

Abstract

The interplay among frustrated lattice geometry, nontrivial band topology and correlation yields rich quantum states of matter in Kagome systems. A series of recent members in this family, AV3Sb5 (A= K, Rb, Cs), exhibit a cascade of symmetry-breaking transitions, involving the 3Q chiral charge ordering, electronic nematicity, roton pair-density-wave and superconductivity. The nature of the superconducting order is yet to be resolved. Here, we report an indication of chiral superconducting domains with boundary supercurrents in intrinsic CsV3Sb5 flakes. Magnetic field-free superconducting diode effect is observed with polarity modulated by thermal histories, suggesting dynamical superconducting order domains in a spontaneous time-reversal symmetry breaking background. Strikingly, the critical current exhibits the double-slit superconducting interference patterns when subjected to an external magnetic field. 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 chiral superconducting order, opening a potential for exploring exotic physics, e.g. Majorana zero modes, in this intriguing topological Kagome system.