Ab-initio design of 3D carbyne-based material

Based on the results of ab-initio calculations, a new type of 3D carbon-based material, where graphene sheets are connected with each other by carbyne chains, is predicted. A simultaneous presence of three different types of hybridization (sp(1)-sp(2)-sp(3)) is shown to be the reason for unusual mechanical properties of this material. Four basic types of such 3D-structures are considered, which differ both in the type of contact bonds of the edge atom of the carbyne chain with graphene sheet and in their location on graphene sheet. "Stress-strain" diagrams for these structures are obtained; their strength and elastic properties are ascertained. It is shown that the strength of contact bond in such a structure can reach 67% of maximum attainable strength, which is realized in five-atom carbyne chain. This is one of the main factors, which guarantees extremely high levels of strength of considered 3D-structures. The linear dependence between the strength of contact bond and its equilibrium length is established, which determines the regularities of atomic structure effect on the strength of such structures. It is shown that a combination of high strength with relatively low values of elasticity moduli is a characteristic feature of considered 3D-structures, which is very attractive for both nano-devices and medical applications. (C) 2016 Elsevier B. V. All rights reserved.