  Due to their anisotropy, layered materials are excellent candidates for
studying the interplay between the in-plane and out-of-plane entanglement in
strongly correlated systems. A relevant example is provided by 1T-TaS2, which
exhibits a multifaceted electronic and magnetic scenario due to the existence
of several charge density wave (CDW) configurations. It includes quantum hidden
phases, superconductivity and exotic quantum spin liquid (QSL) states, which
are highly dependent on the out-of-plane stacking of the CDW. In this system,
the interlayer stacking of the CDW is crucial for the interpretation of the
underlying electronic and magnetic phase diagram. Here, thin-layers of 1T-TaS2
are integrated in vertical van der Waals heterostructures based on few-layer
graphene (FLG) contacts and their electrical transport properties are measured.
Different activation energies in the conductance and a gap at the Fermi level
are clearly observed. Our experimental findings are supported by fully
self-consistent DFT+U calculations, which evidence the presence of an energy
gap in the few-layer limit, not necessarily coming from the formation of
out-of-plane spin-paired bilayers at low temperatures, as previously proposed
for the bulk. These results highlight dimensionality as a key effect for
understanding the properties of 1T-TaS2 and opens the door to the possible
experimental realization of low-dimensional QSLs.
