En route to superhard and 1D conductive carbon allotropes via unusualsp2-sp3 bonding configuration

Carbon structures with sp2-sp3 hybrid bonds were expected to exhibit both excellent mechanical and electronic properties. Here, we theoretically design several unique carbon structures, which contain unusual sp2-sp3 hybrid bonds. We found that the introduction of sp2 bonding units into carbon structure with sp3 bonding can tune the electronic densities of state at Fermi level, especially resulting in 1D conductive channels in 3D structures. Further simulations indicate that Vickers hardness of these structures is close to diamond via the increase in sp3 building blocks. Our current work provides insights into the design of carbon structures with both excellent superhard and remarkably metallic properties.