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

Zullo, Ludovica; Marini, Giovanni; Cren, Tristan; Calandra, Matteo · Nano Lett · 2023

basic_science · Level V

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Abstract

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 × 10<sup>14</sup> e<sup>-</sup> cm<sup>-2</sup> 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)<sub>1.27</sub>(SnSe<sub>2</sub>)<sub>2</sub>. Our work paves the way to the design synthesis of misfit compounds with tailored physical properties.