Effect of hydrogen coverage on elastic response and acoustic wave propagation of SiC sheet

The effect of incomplete sp3 hybridization on the elastic properties and sound velocities of silicene-graphene sheet is studied by the mean of ab initio density functional theory. Upon hydrogenation, it is found that all the structures are stiffer with their high in-plane Young modulus compared to silicene. Moreover, their large Poisson ratios make them stronger and more incompressible than graphene. The examination of the polar plots shows a small anisotropy for system with incomplete sp3 hybridization. The propagation of both shear and compressional acoustic waves are mainly affected by the change in hybridization that largely reduces their values along the zigzag direction. The results of this work establish an issue of technological impact in nanomechanics.