Anisotropic proximity-induced superconductivity and edge supercurrent in Kagome metal, K1-xV3Sb5

TL;DR

This study demonstrates anisotropic proximity-induced superconductivity and edge supercurrents in K1-xV3Sb5, revealing potential for unconventional superconductivity driven by magnetic and topological properties in Kagome metals.

Contribution

It reports the fabrication of Josephson Junctions in K1-xV3Sb5 and uncovers anisotropic magnetic effects and edge states influencing superconductivity, a novel insight into Kagome metal physics.

Findings

Magnetoresistance depends on magnetic field direction.

Critical current is suppressed by out-of-plane magnetic field.

Evidence of edge states from fast oscillations.

Abstract

Materials with transition metals in triangular lattices are of great interest for their potential combination of strong correlation, exotic magnetism and electronic topology. Kagome nets are of particular importance since the discovery of geometrically frustrated magnetism and topological band structures in crystals like Herbertsmithite and Fe3Sn2, respectively. KV3Sb5 was discovered to be a layered topological metal with a Kagome net of vanadium. Here, we fabricated Josephson Junctions (JJ) of K1-xV3Sb5 and induced superconductivity over long junction lengths. Through magnetoresistance and current vs. phase measurements, we observed magnetic field sweeping direction dependent magnetoresistance, and an anisotropic interference pattern with a Fraunhofer pattern for in-plane magnetic field, but a suppression of critical current for out-of-plane magnetic field. These results indicate an anisotropic internal magnetic field in K1-xV3Sb5 which influences the superconducting coupling in the junction, possibly giving rise to spin-triplet superconductivity. In addition, the observation of long-lived fast oscillations shows evidence of spatially localized conducting channels arising from edge states. These observations pave the way for studying unconventional superconductivity and Josephson device based on Kagome metals with electron correlation and topology.