Misfit layer compounds as ultra-tunable field effect transistors: from charge transfer control to emergent superconductivity

TL;DR

This study reveals how misfit layer compounds function as ultra-tunable field effect transistors with controllable charge transfer, enabling the design of emergent superconductivity through alloying strategies.

Contribution

The paper provides a first-principles understanding of charge transfer mechanisms in misfit compounds and demonstrates their potential as highly tunable electronic devices.

Findings

Rocksalt units act as donors, dichalcogenides as acceptors.

Charge transfer can reach 6×10^{14} e^-cm^{-2} and is tunable via alloying.

Strategy for designing emergent superconductivity demonstrated.

Abstract

Misfit layer compounds are heterostructures composed of rocksalt units stacked with few layers 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 ultra-tunable field effect transistors where a charging as large as 6\times10^{14} 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}(SnSe_2)_2. Our work paves the way to the design synthesis of misfit compounds with tailored physical properties.