  Two-dimensional (2D) transition metal dichalcogenides (TMDs) is a versatile
class of quantum materials of interest to various fields including, e.g.,
nanoelectronics, optical devices, and topological and correlated quantum
matter. Tailoring the electronic properties of TMDs is essential to their
applications in many directions. Here, we report that a highly controllable and
uniform on-chip 2D metallization process converts a class of atomically thin
TMDs into robust superconductors, a property belonging to none of the starting
materials. As examples, we demonstrate the introduction of superconductivity
into a class of 2D air-sensitive topological TMDs, including monolayers of
Td-WTe2, 1T'-MoTe2 and 2H-MoTe2, as well as their natural and twisted bilayers,
metalized with an ultrathin layer of Palladium. This class of TMDs are known to
exhibit intriguing topological phases ranging from topological insulator, Weyl
semimetal to fractional Chern insulator. The unique, high-quality
two-dimensional metallization process is based on our recent findings of the
long-distance, non-Fickian in-plane mass transport and chemistry in 2D that
occur at relatively low temperatures and in devices fully encapsulated with
inert insulating layers. Highly compatible with existing nanofabrication
techniques for van der Waals (vdW) stacks, our results offer a route to
designing and engineering superconductivity and topological phases in a class
of correlated 2D materials.
