Tunable mechanical properties of diamond superlattices generated by interlayer bonding in twisted bilayer graphene

Using molecular-dynamics simulations of tensile deformation and shear loading tests, we determine the mechanical properties of superlattices of diamond-like nanocrystals embedded in twisted bilayer graphene (TBG) generated by covalent interlayer bonding through patterned hydrogenation. We find that the mechanical properties of these superstructures can be precisely tuned by controlling the fraction of sp(3)-hybridized C-C bonds in the material, f(sp3), through the extent of chemical functionalization. The Young modulus and ultimate tensile strength weaken compared with pristine TBG with increasing f(sp3), but they remain superior to those of most conventional materials. The interlayer shear modulus increases monotonically with f(sp3). (C) 2013 AIP Publishing LLC.