Layer-sliding-mediated controllable synthetic strategy for the preparation of multifunctional materials

Abstract

Strategies capable of inducing multifunctionality in materials in a controllable manner are highly desirable. In this work, we have brought multifunctionality to a two-dimensional (2D) van der Waals heterostructure (vdW-HS) consisting of a layer of puckered silicene and indium selenide (InSe) through layer-sliding. Electronic, optical and interfacial properties of silicene/InSe vdW-HS have been varied dynamically by sliding silicene over InSe. The aforementioned layer-sliding is carried out in a gradual manner without and with Mg-intercalation. The buckling parameter relating to the corrugation of silicene drops from 0.438 Å to 0.351 Å on Mg-intercalation, whereas in the case of InSe buckling remains unaffected. The calculated band structure for un-intercalated vdW-HS shows a small band gap opening 205/210 meV with LDA/GGA functional) along high symmetry K direction in the first Brillion zone. The widening of the bandgap makes it suitable for optoelectronics and strain sensor devices, where a small band gap (0.1–1 eV) is required. To look inside into the interface of the vdW-HS, various interfacial electronic parameters such as planar average charge density difference (Δρ), dipole charge transfer (ΔQ) and dipole moment (Δµ) have been determined. It is found that the charge accumulation peaks have appeared near the silicene layer and the charge is transferred from silicene to the InSe layer in both un-intercalated and Mg-intercalated vdW-HSs. Further, we investigated the different optical parameters including real [ε1(ω)] and imaginary [ε2(ω)] parts of dielectric function (DF), energy loss function [L(ω)] and diagonal components of dielectric tensor [ε (iω)] for un-intercalated and Mg-intercalated vdW-HSs. The anisotropic analysis shows that the computed in-plane components significantly dominate the out-of-plane component of the DF, which show minor change as the sliding proceeds. The study endorses that multifunctional electronic 2D materials can be achievable by employing the layer-sliding dynamical strategy.