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The electronic band structures, structural, and elastic properties of monolayer MoS 2 under the biaxial strains are investigated using DFT and DFT + U methods. Significant changes in the bond distances, bond angles, electronic structures, and effective mass of electron m e * (hole m h * ) are observed under biaxial strain. The Bulk modulus decreases (increases) by increasing the tensile (compressive) biaxial strain. The band-gap values of unstrained 1L-MoS 2 are estimated as 1.78 (1.81) eV within the GGA (GGA + U) approximations; however, direct band gap varies from 1.74 (1.76) to 1.92 (1.95) eV within a region of 0.3(0.4)% tensile to 1.13(1.11)% compressive strains. Beyond this strain region, direct nature of the band gap becomes indirect, and further increment causes semiconductor to metallic transition. Direct bandgap tuning and observed small effective mass values of electrons and holes carriers under applied strain indicate the enhanced optoelectronic properties in strained monolayer MoS 2 .

Methods capable of tuning the properties of van der Waals (vdW) layered materials in a controlled and reversible manner are highly desirable. Interfacial electronic properties of two-dimensional vdW heterostructure consisting of silicene and indium selenide (InSe) have been calculated using density functional theory-based computational code. Furthermore, in order to vary the aforementioned properties, silicene is slid over a InSe layer in the presence of Li intercalation. On intercalation of the heterostructure, the buckling parameter associated with the corrugation of silicene decreases from 0.44 Å to 0.36 Å, whereas the InSe structure remains unaffected. Potential energy scans reveal a significant increase in the sliding energy barrier for the case of intercalated heterostructure as compared with the unintercalated heterostructure. The sliding of the silicene encounters the maximum energy barrier of 0.14 eV. Anisotropic analysis shows the noteworthy differences between calculated in-plane and out-of-plane part of dielectric function. A variation of the planar average charge density difference, dipole charge transfer and dipole moment have been discussed to elucidate the usability spectrum of the heterostructure. The employed approach based on intercalation and layer sliding can be effectively utilized for obtaining next-generation multifunctional devices.

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