  Setting up strong Josephson coupling in van der Waals materials in close
proximity to superconductors offers several opportunities both to inspect
fundamental physics and to develop novel cryogenic quantum technologies. Here
we show evidence of Josephson coupling in a planar few-layer black Phosphorus
junction. The planar geometry allows us to probe the junction behavior by means
of external gates, at different carrier concentrations. Clear signatures of
Josephson coupling are demonstrated by measuring supercurrent flow through the
junction at milli Kelvin temperatures. Manifestation of Fraunhofer pattern with
a transverse magnetic field is also reported, confirming the Josephson
coupling. These findings represent the first evidence of proximity Josephson
coupling in a planar junction based on a van der Waals material beyond graphene
and open the way to new studies, exploiting the peculiar properties of
exfoliated black phosphorus thin flakes.

Mesoscale and Nanoscale Physics;Quantum Physics