Herein, we systematically studied the electronic, optical, and mechanical properties of a hydrogenated (6,0) single-walled carbon nanotube [(6,0) h-SWCNT] under applied uniaxial stress from first-principles density functional theory (DFT) and molecular dynamics (MD) simulation. We have applied the uniaxial stress range from −18 to 22 GPa on the (6,0) h-SWCNT (− sign indicates compressive and + indicates tensile stress) along the tube axes. Our system was found to be an indirect semiconductor (Γ−Δ), with a band gap value of ∼0.77 eV within the linear combination of atomic orbitals (LCAO) method using a GGA-1/2 exchangecorrelation approximation. The band gap for (6,0) h-SWCNT significantly varies with the application of stress. The indirect to direct band gap transition was observed under compressive stress (−14 GPa). The strained (6,0) h-SWCNT showed a strong optical absorption in the infrared region. Application of external stress enhanced the optically active region from infrared to Vis with maximum intensity within the Vis-IR region, making it a promising candidate for optoelectronic devices. Ab initio molecular dynamics (AIMD) simulation has been used to study the elastic properties of the (6,0) h-SWCNT which has a strong influence under applied stress.

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Using Density Functional Theory (DFT), 2D hexagonal silicene-ZnS-silicene trilayer heterostructure was studied with van der Waals correction as implemented in Grimme’s method. Small lattice mismatch of about 0.77% only between silicene and ZnS monolayer suggest ease in formation of sandwiched heterostructure. The negative value of total energy at 298 K from MD simulation confirms its ground state stability. Unlike monolayer silicene, our trilayer heterostructure exhibits a direct band gap of 0.63 eV in its equilibrium state. Calculated elastic moduli predict that Si-ZnS-Si has an enhanced ability to resist tensile and shear deformation than the pristine silicene and ZnS monolayer. Due to strong van der Waal’s interaction between the layers, Si-ZnS-Si has much lower thermal coefficient of linear expansion and therefore is more stable against any thermally induced deformation. When a transverse external electric field is applied, we observe direct-to-indirect band gap transition. On increasing the electric field further, the heterostructure remains indirect band gap semiconductor until it abruptly transforms to metallic nature at 1.0 V/Å. Theoretical prediction of heterostructure property presented in this work may provide valuable data for developing future nanoelectronic devices.