  The interplay of electronic correlations, spin-orbit coupling and topology
holds promise for the realization of exotic states of quantum matter. Models of
strongly interacting electrons on honeycomb lattices have revealed rich phase
diagrams featuring unconventional quantum states including chiral
superconductivity and correlated quantum spin Hall insulators intertwining with
complex magnetic order. Material realizations of these electronic states are
however scarce or inexistent. In this work, we propose and show that stacking
1T-TaSe$_{2}$ into bilayers can deconfine electrons from a deep Mott insulating
state in the monolayer to a system of correlated Dirac fermions subject to
sizable spin-orbit coupling in the bilayer. 1T-TaSe$_{2}$ develops a
Star-of-David (SoD) charge density wave pattern in each layer. When the SoD
centers belonging to two adyacent layers are stacked in a honeycomb pattern,
the system realizes a generalized Kane-Mele-Hubbard model in a regime where
Dirac semimetallic states are subject to significant Mott-Hubbard interactions
and spin-orbit coupling. At charge neutrality, the system is close to a quantum
phase transition between a quantum spin Hall and an antiferromagnetic
insulator. We identify a perpendicular electric field and the twisting angle as
two knobs to control topology and spin-orbit coupling in the system. Their
combination can drive it across hitherto unexplored grounds of correlated
electron physics including a quantum tricritical point and an exotic
first-order topological phase transition.
