Diamond-like films from twisted few-layer graphene

The atomic and electronic structures of diamanes, i.e., diamond-like films formed by few-layer moiré graphene with a twist angle $\mathbf{\theta}$ in $\mathbf{00\theta}$ and $\mathbf{\theta00\theta}$ stackings are simulated. Chemical adsorption of light atoms (e.g., hydrogen) or molecules on the surface of such graphene leads to the formation of interlayer bonds and, thus, to the complete sp3-hybridization of carbon atoms in structures. Using the available experimental data on the preparation of moiré graphene structures and diamanes based on untwisted bigraphene, a model is proposed for the possible synthesis of such diamanes from twisted three- and four-layer graphene. A hypothetical moiré diamane crystal formed from stacks of similar four-layer graphene is also considered. The stability of three- and four-layer moiré diamanes and the proposed artificial crystal has been demonstrated. The band gap decreases with an increase in the number of initial layers, but the band gap for the crystal is wider because of the higher strain of C–C' bonds, which in the previous cases bond C and H atoms.