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

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 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.

Giant Third-Order Nonlinear Hall Effect in Misfit Layer Compound (SnS)1.17(NbS2)3

“…The constraint of χ 11 = χ 22 = 3χ 12 = 3χ 21 suppress V ⊥ 3ω response down to zero in NbS 2 . The observation of V ⊥ 3ω and V ⊥ 3ω in AB 3 indicates that the formation of a misfit layer compound greatly changes the crystal structure and the band geometry. − …”

“…In AB 3 , though THE is suppressed in individual NbS 2 due to C 3 symmetry, the intercalation of SnS sublayer modifies the crystal structure to a 2-fold symmetry, thereby giving rise to THE. Moreover, the alternate stacking of sublayers functions as a periodic field effect transistor, with charges transfer between sublayers beyond the modulation effect of an external electric field. , The unique characteristics of misfit layer compounds also give rise to other intriguing physical phenomena such as Ising superconductivity, but still posing questions about the underlying mechanism . Hence the observation of the giant THE in AB 3 provides valuable insights into the electronic properties of misfit layer compounds.…”

Recent Advances in Layered MX2-Based Materials (M = Mo, W and X = S, Se, Te) for Emerging Optoelectronic and Photo(electro)catalytic Applications

“…Two-dimensional material heterostructures can also be directly grown chemically just by mixing the components and using high temperatures, normally using quartz ampoules. These obtained materials are called misfit layered compounds (MLCs) and are very abundant in terms of composition, and chemical and physical properties [332][333][334][335][336][337][338][339][340][341].…”

“…MLCs combine different VdW layers with complex stacking and can be represented by the general ideal formula [(MX) 1+y ] m [TX 2 ] n where M = Sn, Pb, Bi, Sb, Y, and rare earth elements; T = Sn, Nb, Ta, Ti, V, Cr; and X = S, Se, Te; TX 2 represents the TMD layer and MX is a rocksalt monochalcogenide layer [333][334][335][336][337]. The right combination of both stacked subunits forms a superstructure and layered or even tubular morphologies can be obtained.…”

“…As subunits of different compositions and repetitive patterns are obtained, electronic and physical properties can be tuned. In this sense, several studies have been published investigating the properties of this class of materials and have suggested industrial applications [333][334][335][336][337].…”