A superhard sp3 microporous carbon with direct bandgap

Carbon allotropes with distinct sp, sp(2), and sp(3) hybridization possess various different properties. Here, a novel all-sp(3) hybridized tetragonal carbon, namely the P carbon, was predicted by the evolutionary particle swarm structural search. It demonstrated a low density among all-sp(3) carbons, due to the corresponding distinctive microporous structure. P carbon is thermodynamically stable than the known C-60 and could be formed through the single-walled carbon nanotubes (SWCNTs) compression. P carbon is a direct bandgap semiconductor displaying a strong and superhard nature. The unique combination of electrical and mechanical properties constitutes P carbon a potential superhard material for semiconductor industrial fields. (C) 2017 Elsevier B.V. All rights reserved.