We perform {textit ab initio} calculations for the strain-induced formation of non-hexagonal-ring defects in graphene, graphane (planar CH), and graphenol (planar COH). We find that the simplest of such topological defects, the Stone-Wales defect, ac
ts as a seed for strain-induced dissociation and multiplication of topological defects. Through the application of inhomogeneous deformations to graphene, graphane and graphenol with initially small concentrations of pentagonal and heptagonal rings, we obtain several novel stable structures that possess, at the same time, large concentrations of non-hexagonal rings (from fourfold to elevenfold) and small formation energies.
Ab initio calculations indicate that topological-defect networks in graphene display the full variety of single-particle electronic structures, including Dirac-fermion null-gap semiconductors, as well as metallic and semiconducting systems of very lo
w formation energies with respect to a pristine graphene sheet. Corrugation induced by the topological defects further reduces the energy and tends to reduce the density of states at the Fermi level, to widen the gaps, or even to lead to gap opening in some cases where the parent planar geometry is metallic.
