Using strain to control molecule chemisorption on silicene.

The strain dependence of benzene chemisorption on a silicene freestanding layer has been studied by means of density functional theory calculations. It appears that the molecule, which is adsorbed via a [4+2] pseudo-cycloaddition on the substrate, is more stable when adsorbed on strained than on unstrained silicene since the adsorption energy increases (in absolute value) with tensile or compressive strain. These results, which were not easily predictable, are interpreted in terms of strain-induced reinforcement of the Si-C bonds, formation of a p _z -like atomic orbital at the silicene atoms, which augments the silicene reactivity and, for compressive or large tensile strains, increasing of the sp ³ character of the Si-Si bonds.