  We report results of investigation of the current-carrying capacity of
nanowires made from the quasi-1D van der Waals metal tantalum triselenide
capped with quasi-2D boron nitride. The chemical vapor transport method
followed by chemical and mechanical exfoliation were used to fabricate mm-long
TaSe3 wires with lateral dimensions in the 20 to 70 nm range. Electrical
measurements establish that TaSe3/h-BN nanowire heterostructures have a
breakdown current density exceeding 10 MA/cm2 - an order-of-magnitude higher
than that in copper. Some devices exhibited an intriguing step-like breakdown,
which can be explained by the atomic thread bundle structure of the nanowires.
The quasi-1D single crystal nature of TaSe3 results in low surface roughness
and the absence of grain boundaries; these features potentially can enable the
downscaling of these wires to lateral dimensions in the few-nm range. These
results suggest that quasi-1D van der Waals metals have potential for
applications in the ultimately downscaled local interconnects.
