Misfit Layer Compounds as Ultratunable Field Effect Transistors: From Charge Transfer Control to Emergent...

Misfit layer compounds are heterostructures composed of rocksalt units stacked with few-layer transition metal dichalcogenides. They host Ising superconductivity, charge density waves, and good thermoelectricity. The design of misfits' emergent properties is, however, hindered by the lack of a global understanding of the electronic transfer among the constituents. Here, by performing first-principles calculations, we unveil the mechanism controlling the charge transfer and demonstrate that rocksalt units are always donor and dichalcogenides acceptors. We show that misfits behave as a periodic arrangement of ultratunable field effect transistors where a charging as large as ≈6 × 10¹⁴ e^- cm^-2 can be reached and controlled efficiently by the La-Pb alloying in the rocksalt. Finally, we identify a strategy to design emergent superconductivity and demonstrate its applicability in (LaSe)_1.27(SnSe₂)₂. Our work paves the way to the design synthesis of misfit compounds with tailored physical properties.