Emergent properties of misfit layer compounds from first principles.

Misfit layer compounds (MLCs) are heterostructures composed of rocksalt units stacked with few-layers transition metal dichalcogenides (TMDs). They host Ising superconductivity, charge density waves, and good thermoelectricity. However, research has mostly focused on specific compounds and trial-and-error synthesis, making the design of misfits’ emergent properties hindered by a lack of a global picture. Our work offers an original perspective by deriving misfits’ properties from those of their constituent layers. We identify the fundamental mechanism governing charge transfer and demonstrate how charge injection into the TMD layers can be effectively controlled through chemical alloying in the rocksalt unit. We show that misfits behave as a periodic arrangement of ultra-tunable field-effect transistors, allowing for massive chargings. We establish a strategy to study the electronic and vibrational properties of MLCs, highlighting the two-dimensional nature of the lattice dynamics of TMDs in these three-dimensional hetrostructures. Finally, we present an in-depth study of superconductivity in MLCs, estimating critical temperatures and comparing with existent experimental data. Our work provides a complete characterization of these heterostructures, aiming to guide the design of materials with targeted emergent properties for future device applications.