Computer simulations of nanostructured carbon under tensile load: Electronic structure and optical gap

We use computer simulations to study the behavior of amorphous carbon and carbon composites under tensile strain. We investigate the behavior of the optoelectronic properties of these materials as strain is increased. These properties are monitored through the electronic density of states, the optical gap and the Urbach energy for both materials. The variation in the hybrid (sp2 and sp3) content due to the external load is directly connected to changes in the optoelectronic properties with increasing strain. This connection will lead to interesting features in the Urbach edge for the amorphous network, while the respective effect for the nanocomposite will be less pronounced. The situation is reversed when the optical gap is used as a probe of the properties of both amorphous and composite materials.

► We model amorphous carbon and diamond composite networks using a tight-binding molecular dynamics scheme.
► Tensile strain is applied on both networks up to their fracture point.
► The electronic structure, Urbach energy and optical gaps of the strained networks are extracted from the simulations.
► The variation of the optical gaps and Urbach energy with the hybridization content is discussed.