1T-TaS₂ as a quantum spin liquid: from bulk to atomically-thin layers.

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 shows a multifaceted electronic and magnetic scenario due to the existence of several charge density waves (CDW) configurations, including quantum hidden phases, superconductivity and even quantum spin liquid (QSL) phases, that are highly dependent on the out-of-plane stacking of the CDW.

Here, we report on bulk and atomically thin-layers of 1T-TaS₂. For bulk, we show experimental evidence for several competing quantum phases, obtained by combining temperature-dependent muon spin relaxation and specific heat measurements, with a switching on the spinon density of states versus energy [1]. Regarding atomically-thin layers of 1T-TaS₂, we fabricate vertical van der Waals heterostructures based on few-layer graphene and we measure their transport properties. Different activation energies in the conductance and a gap at the Fermi level are observed, which may indicate a progressive formation of out-of-plane spin-paired bilayers at low temperatures [2]. These features make 1T-TaS₂ a potential candidate for hosting multiple QSL crossovers.

1. arXiv:2007.15905, 2020
2. arXiv:2009.14550, 2020