Out-of-plane charge density wave structure of the 1T-TaS2 quantum spin liquid in the thin-layer limit: a van der Waals heterostructure approach.

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 waves (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 heterostructures based on fewlayer graphene contacts and their electrical transport properties are measured. Different activation energies in the conductance and a gap at the Fermi level are observed, which may be indicative of a progressive formation of out-of-plane spin-paired bilayers at low temperatures. This makes 1TTaS2 a potential candidate for hosting multiple QSL crossovers.